Targeted cytolysis of HIV-infected cells by chimeric CD4 receptor-bearing cells

ABSTRACT

Disclosed is a method of directing a cellular immune response against an HIV-infected cell in a mammal involving administering to the mammal an effective amount of therapeutic cells which express a membrane-bound, proteinaceous chimeric receptor comprising (a) an extracellular portion which includes a fragment of CD4 which is capable of specifically recognizing and binding the HIV-infected cell but which does not mediate HIV infection and (b) an intracellular portion which is capable of signalling the therapeutic cell to destroy the receptor-bound HIV-infected cell. Also disclosed is a second method of treating HIV in a mammal involving administering to the mammal an effective amount of therapeutic cells expressing a membrane-bound, proteinaceous chimeric receptor comprising an extracellular portion which includes a fragment of CD4 which is capable of specifically recognizing and binding the HIV-infected cell but which does not mediate HIV infection. Also disclosed are cells which express the chimeric receptors and DNA and vectors encoding the chimeric receptors.

FIELD OF THE INVENTION

This application is a continuation-in-part of Seed et al., U.S. Ser. No.08/284,391, filed Aug. 2, 1994, now issued as U.S. Pat. No. 5,851,828,which is a continuation-in-part of Seed et al., U.S. Ser. No.08/195,395, filed Feb. 14, 1994, now abandoned, which is acontinuation-in-part of Seed et al., U.S. Ser. No. 07/847,566, filedMar. 6, 1992, now abandoned, which is a continuation-in-part of Seed etal., U.S. Ser. No. 07/665,961, filed Mar. 7, 1991, now abandoned.

The invention concerns functional chimeras between CD4 fragments andimmune cell receptors which are capable of directing immune cells tolyse HIV-infected cells, but which do not render the immune cellssusceptible to HIV infection. The invention therefore provides a noveland effective HIV therapeutic.

BACKGROUND OF THE INVENTION

T cell recognition of antigen through the T cell receptor is the basisof a range of immunological phenomena. The T cells direct what is calledcell-mediated immunity. This involves the destruction by cells of theimmune system of foreign tissues or infected cells. A variety of T cellsexist, including “helper” and “suppressor” cells, which modulate theimmune response, and cytotoxic (or “killer”) cells, which can killabnormal cells directly.

A T cell that recognizes and binds a unique antigen displayed on thesurface of another cell becomes activated; it can then multiply, and, ifit is a cytotoxic cell, it can kill the bound cell. HIV andImmunopathogenesis

In 1984 HIV was shown to be the etiologic agent of AIDS. Since that timethe definition of AIDS has been revised a number of times with regard towhat criteria should be included in the diagnosis. However, despite thefluctuation in diagnostic parameters, the simple common denominator ofAIDS is the infection with HIV and subsequent development of persistentconstitutional symptoms and AIDS-defining diseases such as a secondaryinfections, neoplasms, and neurologic disease. Harrison's Principles ofInternal Medicine, 12th ed., McGraw Hill (1991).

HIV is a human retrovirus of the lentivirus group. The four recognizedhuman retroviruses belong to two distinct groups: the human Tlymphotropic (or leukemia) retroviruses, HTLV-1 and HTLV-2, and thehuman immunodeficiency viruses, HIV-1 and HIV-2. The former aretransforming viruses whereas the latter are cytopathic viruses.

HIV-1 has been identified as the most common cause of AIDS throughoutthe world. Sequence homology between HIV-2 and HIV-1 is about 40% withHIV-2 being more closely related to some members of a group of simianimmunodeficiency viruses (SIV). See Curran et al., Science 329:1357-1359(1985); Weiss et al., Nature 324:572-575 (1986).

HIV has the usual retroviral genes (env, gag, and pol) as well as sixextra genes involved in the replication and other biologic activities ofthe virus. As stated previously, the common denominator of AIDS is aprofound immunosuppression, predominantly of cell-mediated immunity.This immune suppression leads to a variety of opportunistic diseases,particularly certain infections and neoplasms.

The main cause of the immune defect in AIDS has been identified as aquantitative and qualitative deficiency in the subset of thymus-derived(T) lymphocytes, the T4 population. This subset of cells is definedphenotypically by the presence of the CD4 surface molecule, which hasbeen demonstrated to be the cellular receptor for HIV. Dalgleish et al.,Nature 312:763 (1984). Although the T4 cell is the major cell typeinfected with HIV, essentially any human cell that expresses the CD4molecule on its surface is capable of binding to and being infected withHIV.

Traditionally, CD4⁺ T cells have been assigned the role ofhelper/inducer, indicating their function in providing an activatingsignal to B cells, or inducing T lymphocytes bearing the reciprocal CD8marker to become cytotoxic/suppressor cells. Reinherz and Schlossman,Cell 19:821-827 (1980); Goldstein et al., Immunol. Rev. 68:5-42 (1982).

HIV binds specifically and with high affinity, via a stretch of aminoacids in the viral envelope (gp120), to a portion of the V1 region ofthe CD4 molecule located near its N-terminus. Following binding, thevirus fuses with the target cell membrane and is internalized. Onceinternalized it uses the enzyme reverse transcriptase to transcribe itsgenomic RNA to DNA, which is integrated into the cellular DNA where itexists for the life of the cell as a “provirus.”

The provirus may remain latent or be activated to transcribe MRNA andgenomic RNA, leading to protein synthesis, assembly, new virionformation, and budding of virus from the cell surface. Although theprecise mechanism by which the virus induces cell death has not beenestablished, it is believed that the major mechanism is massive viralbudding from the cell surface, leading to disruption of the plasmamembrane and resulting osmotic disequilibrium.

During the course of the infection, the host organism developsantibodies against viral proteins, including the major envelopeglycoproteins gp120 and gp41. Despite this humoral immunity, the diseaseprogresses, resulting in a lethal immunosuppression characterized bymultiple opportunistic infections, parasitemia, dementia, and death. Thefailure of the host anti-viral antibodies to arrest the progression ofthe disease represents one of the most vexing and alarming aspects ofthe infection, and augurs poorly for vaccination efforts based uponconventional approaches.

Two factors may play a role in the efficacy of the humoral response toimmunodeficiency viruses. First, like other RNA viruses (and likeretroviruses in particular), the immunodeficiency viruses show a highmutation rate in response to host immune surveillance. Second, theenvelope glycoproteins themselves are heavily glycosylated moleculespresenting few epitopes suitable for high affinity antibody binding. Thepoorly antigenic target which the viral envelope presents allows thehost little opportunity for restricting viral infection by specificantibody production.

Cells infected by the HIV virus express the gp120 glycoprotein on theirsurface. Gp120 mediates fusion events among CD4⁺ cells via a reactionsimilar to that by which the virus enters the uninfected cells, leadingto the formation of short-lived multinucleated giant cells. Syncytiumformation is dependent on a direct interaction of the gp120 envelopeglycoprotein with the CD4 protein. Dalgleish et al., supra; Klatzman etal., Nature 312:763 (1984); McDougal et al., Science 231:382 (1986);Sodroski et al., Nature 322:470 (1986); Lifson et al., Nature 323:725(1986); Sodroski et al., Nature 321:412 (1986).

Evidence that the CD4-gp120 binding is responsible for viral infectionof cells bearing the CD4 antigen includes the finding that a specificcomplex is formed between gp120 and CD4 (McDougal et al., supra). Otherinvestigators have shown that the cell lines, which were non-infectivefor HIV, were converted to infectable cell lines following transfectionand expression of the human CD4 cDNA gene. Maddon et al., Cell46:333-348 (1986).

Therapeutic programs based on soluble CD4 as a passive agent tointerfere with viral adsorption and syncytium-mediated cellulartransmission have been proposed and successfully demonstrated in vitroby a number of groups (Deen et al., Nature 331:82-84 (1988); Fisher etal., Nature 331:76-78 (1988); Hussey et al., Nature 331:78-81 (1988);Smith et al., Science 238:1704-1707 (1987); Traunecker et al., Nature331:84-86 (1988)); and CD4 immunoglobulin fusion proteins with extendedhalf-lives and modest biological activity have subsequently beendeveloped (Capon et al., Nature 337:525-531 (1989); Traunecker et al.Nature 339, 68-70 (1989); Byrn et al., Nature 344:667-670 (1990);Zettlmeissl et al., DNA Cell Biol. 9:347-353 (1990)). Although CD4immunotoxin conjugates or fusion proteins show potent cytotoxicity forinfected cells in vitro (Chaudhary et al., Nature 335:369-372 (1988);Till et al., Science 242:1166-1168 (1988)), the latency of theimmunodeficiency syndrome makes it unlikely that any single-treatmenttherapy will be effective in eliminating viral burden, and theantigenicity of foreign fusion proteins is likely to limit theiracceptability in treatments requiring repetitive dosing. Trials withmonkeys affected with SIV have shown that soluble CD4, if administeredto animals without marked CD4 cytopenia, can reduce SIV titer andimprove in vitro measures of myeloid potential (Watanabe et al., Nature337:267-270 (1989)). However a prompt viral reemergence was observedafter treatment was discontinued, suggesting that lifelongadministration might be necessary to prevent progressive immune systemdebilitation.

T Cell and Fc Receptors

Cell surface expression of the most abundant form of the T cell antigenreceptor (TCR) requires the coexpression of at least 6 distinctpolypeptide chains (Weiss et al., J. Exp. Med. 160:1284-1299 (1984);Orloffhashi et al., Nature 316:606-609 (1985); Berkhout et al., J. Biol.Chem. 263:8528-8536 (1988); Sussman et al., Cell 52:85-95 (1988)), theα/β antigen binding chains, the three polypeptides of the CD3 complex,and ζ. If any of the chains are absent, stable expression of theremaining members of the complex does not ensue. ζ is the limitingpolypeptide for surface expression of the complete complex (Sussman etal., Cell 52:85-95 (1988)) and is thought to mediate at least a fractionof the cellular activation programs triggered by receptor recognition ofligand (Weissman et al., EMBO J. 8:3651-3656 (1989); Frank et al.,Science 249:174-177 (1990)). A 32 kDa type I integral membranehomodimer, ζ (zeta) has a 9 residue extracellular domain with no sitesfor N-linked glycan addition, and a 112 residue (mouse) or 113 residue(human) intracellular domain (Weissman et al., Science 238:1018-1020(1988); Weissman et al., Proc. Natl. Acad. Sci. USA 85:9709-9713(1988)). An isoform of ζ called η (eta) (Baniyash et al., J. Biol. Chem.263:9874-9878 (1988); Orloff et al., J. Biol. Chem. 264:14812-14817(1989)), which arises from an alternate mRNA splicing pathway (Jin etal., Proc. Natl. Acad. Sci. USA 87:3319-3233 (1990)), is present inreduced amounts in cells expressing the antigen receptor. ζ−ηheterodimers are thought to mediate the formation of inositolphosphates, as well as the receptor-initiated programmed cell deathcalled apoptosis (Merćep et al., Science 242:571-574 (1988); Merćep etal., Science 246:1162-1165 (1989)).

Like ζ and η, the Fc receptor-associated γ (gamma) chain is expressed incell surface complexes with additional polypeptides, some of whichmediate ligand recognition, and others of which have undefined function.γ bears a homodimeric structure and overall organization very similar tothat of ζ and is a component of both the mast cell/basophil highaffinity IgE receptor, FcεRI, which consists of at least three distinctpolypeptide chains (Blank et al., Nature 337:187-189 (1989); Ra et al.,Nature 241:752-754 (1989)), and one of the low affinity receptors forIgG, represented in mice by FcγRIIα (Ra et al., J. Biol. Chem.264:15323-15327 (1989)), and in humans by the CD16 subtype expression bymacrophages and natural killer cells, CD16_(TM) (CD16 transmembrane)(Lanier et al., Nature 342:803-805 (1989); Anderson et al., Proc. Natl.Acad. Sci. USA 87:2274-2278 (1990)) and with a polypeptide ofunidentified function (Anderson et al., Proc. Natl. Acad. Sci. USA87:2274-2278 (1990)). Recently it has been reported that γ is expressedby a mouse T cell line, CTL, in which it forms homodimers as well as γ−ζand γ−η heterodimers (Orloff et al., Nature 347:189-191 (1990)).

The Fc receptors mediate phagocytosis of immune complexes, transcytosis,and antibody dependent cellular cytotoxicity (ADCC) (Ravetch and Kinet,Annu. Rev. Immunol. 9:457-492 (1991); Unkeless et al., Annu. Rev.Immunol 6:251-281 (1988); and Mellman, Curr. Opin. Immunol. 1:16-25(1988)). Recently it has been shown that one of the murine low affinityFc receptor isoforms, FcRγIIIB1, mediates internalization of Ig-coatedtargets into clathrin coated pits, and that another low affinityreceptor, FcRγIIIA mediates ADCC through its association with one ormore members of a small family of ‘trigger molecules’ (Miettinen et al.,Cell 58:317-327 (1989); and Hunziker and Mellman, J. Cell Biol.109:3291-3302 (1989)). These trigger molecules, T cell receptor (TCR) ζchain, TCR η chain, and Fc receptor γ chain, interact with ligandrecognition domains of different immune system receptors and canautonomously initiate cellular effector programs, including cytolysis,following aggregation (Samelson et al., Cell 43:223-231 (1985); Weissmanet al., Science 239:1018-1020 (1988); Jin et al., Proc. Natl. Acad. Sci.USA 87:3319-3323 (1990); Blank et al., Nature 337:187-189 (1989); Lanieret al., Nature 342:803-805 (1989); Kurosaki and Ravetch, Nature342:805-807 (1989); Hibbs et al., Science 246:1608-1611 (1989); Andersonet al., Proc. Natl. Acad. Sci USA 87:2274-2278 (1990); and Irving andWeiss, Cell 64: 891-901 (1991)).

In drawing parallels between the murine and human low affinity Fcreceptor families, however, it has become clear that the human FcRγIIAand C isoforms have no murine counterpart. In part because of this,their function has yet to be defined.

Because humoral agents based on CD4 alone may have limited utility invivo, previous work explored the possibility of augmenting cellularimmunity to HIV. Preparations of protein chimeras in which theextracellular domain of CD4 is fused to the transmembrane and/orintracellular domains of T cell receptor, IgG Fc receptor, or B cellreceptor signal transducing elements have been identified (U.S. Ser.Nos. 07/847,566 and 07/665,961, hereby incorporated by reference).Cytolytic T cells expressing chimeras which include an extracellular CD4domain show potent MHC-independent destruction of cellular targetsexpressing HIV envelope proteins. An extremely important and novelcomponent of this approach has been the identification of single T cellreceptor, Fc receptor, and B cell receptor chains whose aggregationsuffices to initiate the cellular response. One particularly usefulapplication of this approach has been the invention of chimeras betweenCD4 and ζ, η, or γ that direct cytolytic T lymphocytes to recognize andkill cells expressing HIV gp120 (U.S. Ser. Nos. 07/847,566 and07/665,961, hereby incorporated by reference).

SUMMARY OF HE INVENTION

In general, the invention features a method of directing a cellularimmune response against an HIV-infected cell in a mammal. The methodinvolves administering to the mammal an effective amount of therapeuticcells, the therapeutic cells expressing a membrane-bound, proteinaceouschimeric receptor comprising (a) an extracellular portion which includesa fragment of CD4 which is capable of specifically recognizing andbinding the HIV-infected cell but which does not mediate HIV infectionand (b) an intracellular portion which is capable of signalling thetherapeutic cell to destroy the receptor-bound HIV-infected cell.

In a related aspect, the invention features a cell which expresses aproteinaceous membrane-bound chimeric receptor which comprises (a) anextracellular portion which includes a fragment of CD4 which is capableof specifically recognizing and binding the HIV-infected cell but whichdoes not mediate HIV infection and (b) an intracellular portion which iscapable of signalling the therapeutic cell to destroy the receptor-boundHIV-infected cell.

In a second aspect, the invention features a method of treating HIV in amammal involving administering to the mammal an effective amount oftherapeutic cells, the therapeutic cells expressing a membrane-bound,proteinaceous chimeric receptor comprising an extracellular portionwhich includes a fragment of CD4 which is capable of specificallyrecognizing and binding the HIV-infected cell but which does not mediateHIV infection.

In a related aspect, the invention features a cell which expresses amembrane-bound, proteinaceous chimeric receptor comprising anextracellular portion which includes a fragment of CD4 which is capableof specifically recognizing and binding the HIV-infected cell but whichdoes not mediate HIV infection.

In preferred embodiments of both the first and second aspects, the CD4fragment is amino acids 1-394 of CD4 or is amino acids 1-200 of CD4; theCD4 fragment is separated from the intracellular portion by the CD7transmembrane domain shown in FIG. 26 or by the hinge, CH2, and CH3domains of the human IgG1 molecule shown in FIG. 25; and the CD4fragment is separated from the therapeutic cell by at least 48 angstroms(and preferably, by at least 72 angstroms). In preferred embodiments ofthe first aspect, the intracellular portion is the signal-transducingportion of a T cell receptor protein (for example, ζ), a B cell receptorprotein, or an Fc receptor protein; and the therapeutic cells areselected from the group consisting of: (a) T lymphocytes; (b) cytotoxicT lymphocytes; (c) natural killer cells; (d) neutrophils; (e)granulocytes; (f) macrophages; (g) mast cells; (h) HeLa cells; and (i)embryonic stem cells (ES).

In other related aspects, the invention features DNA encoding a chimericreceptor of the invention; and a vector including that chimeric receptorDNA.

Although the specific embodiment of the present invention is a chimerabetween CD4 and zeta, any receptor chain having a similar function tothese molecules, e.g., in granulocytes or B lymphocytes, could be usedfor the purposes disclosed here. The distinguishing features of adesirable immune cell trigger molecule comprises the ability to beexpressed autonomously (i.e., as a single chain), the ability to befused to an extracellular CD4 domain such that the resultant chimera ispresent on the surface of a therapeutic cell, and the ability toinitiate cellular effector programs upon aggregation secondary toencounter with a target ligand.

At present the most convenient method for delivery of the chimeras toimmune system cells is through some form of genetic therapy. Howeverreconstituting immune system cells with chimeric receptors by mixture ofthe cells with suitably solubilized purified chimeric protein would alsoresult in the formation of an engineered cell population capable ofresponding to HIV-infected targets. Similar approaches have been used,for example, to introduce the CD4 molecule into erythrocytes fortherapeutic purposes. In this case the engineered cell population wouldnot be capable of self renewal.

The present invention relates to functional and simplified chimerasbetween CD4 fragments and T cell receptor, B cell receptor, and Fcreceptor subunits which are capable of directing immune cells torecognize and lyse HIV-infected cells. The method for directing thecellular response in a mammal comprises administering an effectiveamount of therapeutic cells (for example, cytotoxic T lymphocytes) tothe mammal, the cells being capable of recognizing and destroying theHIV-infected cell.

The invention also includes the chimeric receptor proteins which directthe cytotoxic T lymphocytes to recognize and lyse HIV-infected cells,the host cells transformed with a vector comprising the chimericreceptors, and antibodies directed against the chimeric receptors.

These and other non-limiting embodiments of the present invention willbe apparent to those of skill from the following detailed description ofthe invention.

In the following detailed description, reference will be made to variousmethodologies known to those of skill in the art of molecular biologyand immunology. Publications and other materials setting forth suchknown methodologies to which reference is made are incorporated hereinby reference in their entireties as though set forth in full.

Standard reference works setting forth the general principles ofrecombinant DNA technology include Watson et al., Molecular Biology ofthe Gene, volumes I and II, the Benjamin/Cummings Publishing Company,Inc., publisher, Menlo Park, Calif. (1987); Darnell et al., MolecularCell Biology, Scientific American Books, Inc., publisher, New York, N.Y.(1986); Lewin, Genes II, John Wiley & Sons, publishers, New York, N.Y.(1985); Old et al., Principles of Gene Manipulation: An Introduction toGenetic Engineering, 2nd ed., University of California Press, publisher,Berkeley, Calif. (1981); Maniatis et al., Molecular Cloning: ALaboratory Manual, 2nd ed., Cold Spring Harbor Laboratory, publisher,Cold Spring Harbor, N.Y. (1989); and Ausubel et al., Current Protocolsin Molecular Biology, Wiley Press, New York, N.Y. (1989).

DEFINITIONS

By “cloning” is meant the use of in vitro recombination techniques toinsert a particular gene or other DNA sequence into a vector molecule.

By “cDNA” is meant complementary or copy DNA produced from an RNAtemplate by the action of RNA-dependent DNA polymerase (reversetranscriptase). Thus a “cDNA clone” means a duplex DNA sequencecomplementary to an RNA molecule of interest, carried in a cloningvector.

By “cDNA library” is meant a collection of recombinant DNA moleculescontaining cDNA inserts which comprise DNA copies of mRNA beingexpressed by the cell at the time the cDNA library was made. Such a cDNAlibrary may be prepared by methods known to those of skill, anddescribed, for example, in Ausubel et al., supra and Maniatis et al.,supra. Generally, RNA is first isolated from the cells of an organismfrom whose genome it is desired to clone a particular gene. Preferredfor the purpose of the present invention are mammalian, and particularlyhuman, lymphocytic cell lines. A presently preferred vector for thispurpose is the vaccinia virus WR strain.

By “vector” is meant a DNA molecule derived, e.g., from a plasmid,bacteriophage, or mammalian or insect virus, into which fragments of DNAmay be inserted or cloned. A vector will contain one or more uniquerestriction sites and may be capable of autonomous replication in adefined host or vehicle organism such that the cloned sequence isreproducible. Thus, by “DNA expression vector” is meant any autonomouselement capable of directing the synthesis of a recombinant peptide.Such DNA expression vectors include bacterial plasmids and phages andmammalian and insect plasmids and viruses.

By “substantially pure” is meant a compound, e.g., a protein, apolypeptide, or an antibody, that is substantially free of thecomponents that naturally accompany it. Generally, a compound issubstantially pure when at least 60%, more preferably at least 75%, andmost preferably at least 90% of the total material in a sample is thecompound of interest. Purity can be measured by any appropriate method,e.g., column chromatography, polyacrylamide gel electrophoresis, or HPLCanalysis. In the context of a nucleic acid, “substantially pure” means anucleic acid sequence, segment, or fragment that is not immediatelycontiguous with (i.e., covalently linked to) both of the codingsequences with which it is immediately contiguous (i.e., one at the 5′end and one at the 3′ end) in the naturally occurring genome of theorganism from which the DNA of the invention is derived.

A “fragment” of a molecule, such as any of the cDNA sequences of thepresent invention, is meant to refer to any contiguous nucleotide subsetof the molecule. An “analog” of a molecule is meant to refer to anon-natural molecule substantially similar to either the entire moleculeor a fragment thereof. A molecule is said to be “substantially similar”to another molecule if the sequence of amino acids in both molecules issubstantially the same. In particular, a “substantially similar” aminoacid sequence is one that exhibits at least 50%, preferably 85%, andmost preferably 95% amino acid sequence identity to the natural orreference sequence and/or one that differs from the natural or referenceamino acid sequence only by conservative amino acid substitutions.Substantially similar amino acid molecules will possess a similarbiological activity. As used herein, a molecule is said to be a“chemical derivative” of another molecule when it contains chemicalmoieties not normally a part of the molecule. Such moieties may improvethe molecule's solubility, absorption, biological half life, etc. Themoieties may alternatively decrease the toxicity of the molecule,eliminate or attenuate any undesirable side effect of the molecule, etc.Moieties capable of mediating such effects are disclosed, for example,in Remington's Pharmaceutical Sciences, 16th ed., Mack Publishing Co.,Easton, Pa. (1980).

A “functional derivative” of a receptor chimera gene of the presentinvention is meant to include “fragments” or “analogues” of the gene,which are “substantially similar” in nucleotide sequence. “Substantiallysimilar” nucleic acids encode substantially similar amino acid sequences(as defined above) and also may include any nucleic acid sequencecapable of hybridizing to the natural or reference nucleic acid sequenceunder appropriate hybridization conditions (see, for example, Ausubel etal., Current Protocols in Molecular Biology, Wiley Press, New York, N.Y.(1989) for appropriate hybridization stringency conditions.) A“substantially similar” chimeric receptor possesses similar activity toa “wild-type” T cell, B cell, or Fc receptor chimera. Most preferably,the derivative possesses 90%, more preferably, 70%, and preferably 40%of the wild-type receptor chimera's activity. The activity of afunctional chimeric receptor derivative includes specific binding (withits extracellular CD4 portion) to an HIV-infected cell and resultantdestruction of that cell; in addition, the chimeric receptor does notrender the receptor-bearing cell susceptible to HIV infection. Chimericreceptor activity may be tested using, e.g., any of the assays describedherein.

A DNA sequence encoding the CD4 receptor chimera of the presentinvention, or its functional derivatives, may be recombined with vectorDNA in accordance with conventional techniques, including blunt-ended orstaggered-ended termini for ligation, restriction enzyme digestion toprovide appropriate termini, filling in of cohesive ends as appropriate,alkaline phosphatase treatment to avoid undesirable joining, andligation with appropriate ligases. Techniques for such manipulations aredisclosed by Maniatis et al., supra, and are well known in the art.

A nucleic acid molecule, such as DNA, is said to be “capable ofexpressing” a polypeptide if it contains nucleotide sequences whichcontain transcriptional and translational regulatory information, andsuch sequences are “operably linked” to nucleotide sequences whichencode the polypeptide. An operable linkage is a linkage in which theregulatory DNA sequences and the DNA sequence sought to be expressed areconnected in such a way as to permit gene expression. The precise natureof the regulatory regions needed for gene expression may vary fromorganism to organism, but shall in general include a promoter regionwhich, in prokaryotes, contains both the promoter (which directs theinitiation of RNA transcription) as well as the DNA sequences which,when transcribed into RNA, will signal the initiation of proteinsynthesis. Such regions will normally include those 5′-non-codingsequences involved with initiation of transcription and translation,such as the TATA box, capping sequence, CAAT sequence, and the like.

If desired, the non-coding region 3′ to the gene sequence coding for theprotein may be obtained by the above-described methods. This region maybe retained for its transcriptional termination regulatory sequences,such as termination and polyadenylation. Thus, by retaining the3′-region naturally contiguous to the DNA sequence coding for theprotein, the transcriptional termination signals may be provided. Wherethe transcriptional termination signals are not satisfactorilyfunctional in the expression host cell, then a 3′ region functional inthe host cell may be substituted.

Two DNA sequences (such as a promoter region sequence and a CD4-receptorchimera encoding sequence) are said to be operably linked if the natureof the linkage between the two DNA sequences does not (1) result in theintroduction of a frame-shift mutation, (2) interfere with the abilityof the promoter region sequence to direct the transcription of thereceptor chimera gene sequence, or (3) interfere with the ability of thereceptor chimera gene sequence to be transcribed by the promoter regionsequence. A promoter region would be operably linked to a DNA sequenceif the promoter were capable of effecting transcription of that DNAsequence. Thus, to express the protein, transcriptional andtranslational signals recognized by an appropriate host are necessary.

The present invention encompasses the expression of a CD4-receptorchimera protein (or a functional derivative thereof) in eitherprokaryotic or eukaryotic cells, although eukaryotic (and, particularly,human lymphocyte) expression is preferred.

Antibodies according to the present invention may be prepared by any ofa variety of methods. For example, cells expressing the CD4-receptorchimera protein, or a functional derivative thereof, can be administeredto an animal in order to induce the production of sera containingpolyclonal antibodies that are capable of binding the chimera.

In a preferred method, antibodies according to the present invention aremonoclonal antibodies. Such monoclonal antibodies can be prepared usinghybridoma technology (Kohler et al., Nature 256:495 (1975); Kohler etal., Eur. J. Immunol. 6:511 (1976); Kohler et al., Eur. J. Immunol.6:292 (1976); Hammerling et al., In: Monoclonal Antibodies and T-CellHybridomas, Elsevier, N.Y., pp. 563-684 (1981)). In general, suchprocedures involve immunizing an animal with the CD4-receptor chimeraantigen. The splenocytes of such animals are extracted and fused with asuitable myeloma cell line. Any suitable myeloma cell line may beemployed in accordance with the present invention. After fusion, theresulting hybridoma cells are selectively maintained in HAT medium, andthen cloned by limiting dilution as described by Wands et al.(Gastroenterology 80:225-232 (1981)). The hybridoma cells obtainedthrough such a selection are then assayed to identify clones whichsecrete antibodies capable of binding the chimera.

Antibodies according to the present invention also may be polyclonal,or, preferably, region specific polyclonal antibodies.

Antibodies against the CD4-receptor chimera according to the presentinvention may be used to monitor the amount of chimeric receptor (orchimeric receptor-bearing cells) in a patient. Such antibodies are wellsuited for use in standard immunodiagnostic assays known in the art,including such immunometric or “sandwich” assays as the forwardsandwich, reverse sandwich, and simultaneous sandwich assays. Theantibodies may be used in any number of combinations as may bedetermined by those of skill without undue experimentation to effectimmunoassays of acceptable specificity, sensitivity, and accuracy.

Standard reference works setting forth general principles of immunologyinclude Roitt, Essential Immunology, 6th ed., Blackwell ScientificPublications, publisher, Oxford (1988); Kimball, Introduction toImmunology, 2nd ed., Macmillan Publishing Co., publisher, New York(1986); Roitt et al., Immunology, Gower Medical Publishing Ltd.,publisher, London, (1985); Campbell, “Monoclonal Antibody Technology,”in Burdon et al., eds., Laboratory Techniques in Biochemistry andMolecular Biology, volume 13, Elsevier, publisher, Amsterdam (1984);Klein, Immunology: The Science of Self-Nonself Discrimination, JohnWiley & Sons, publisher, New York (1982); and Kennett et al., eds.,Monoclonal Antibodies. Hybridoma: A New Dimension In BiologicalAnalyses, Plenum Press, publisher, New York (1980).

By “detecting” it is intended to include determining the presence orabsence of a substance or quantifying the amount of a substance. Theterm thus refers to the use of the materials, compositions, and methodsof the present invention for qualitative and quantitativedeterminations.

The antibodies and substantially purified antigen of the presentinvention are ideally suited for the preparation of a kit. Such a kitmay comprise a carrier means being compartmentalized to receive in closeconfinement therewith one or more container means such as vials, tubesand the like, each of said container means comprising the separateelements of the assay to be used.

The types of assays which can be incorporated in kit form are many, andinclude, for example, competitive and non-competitive assays. Typicalexamples of assays which can utilize the antibodies of the invention areradioimmunoassays (RIA), enzyme immunoassays (EIA), enzyme-linkedimmunoadsorbent assays (ELISA), and immunometric, or sandwich,immunoassays.

By the term “immunometric assay” or “sandwich immunoassay,” it is meantto include simultaneous sandwich, forward sandwich, and reverse sandwichimmunoassays. These terms are well understood by those skilled in theart. Those of skill will also appreciate that antibodies according tothe present invention will be useful in other variations and forms ofassays which are presently known or which may be developed in thefuture. These are intended to be included within the scope of thepresent invention.

By “specifically recognizes and binds” is meant that the antibodyrecognizes and binds the chimeric receptor polypeptide but does notsubstantially recognize and bind other unrelated molecules in a sample,e.g., a biological sample.

By “therapeutic cell” is meant a cell which has been transformed by aCD4-receptor chimera of the invention so that it is capable ofrecognizing and destroying an HIV-infected cell; preferably suchtherapeutic cells are cells of the hematopoietic system.

By “extracellular” is meant having at least a portion of the moleculeexposed at the cell surface. By “intracellular” is meant having at leasta portion of the molecule exposed to the therapeutic cell's cytoplasm.By “transmembrane” is meant having at least a portion of the moleculespanning the plasma membrane. An “extracellular portion”, an“intracellular portion”, and a “transmembrane portion”, as used herein,may include flanking amino acid sequences which extend into adjoiningcellular compartments.

By “oligomerize” is meant to complex with other proteins to form dimers,trimers, tetramers, or other higher order oligomers. Such oligomers maybe homo-oligomers or hetero-oligomers. An “oligomerizing portion” isthat region of a molecule which directs complex (i.e., oligomer)formation.

By “cytolytic” is meant to be capable of destroying a cell (e.g., anHIV-infected cell) or to be capable of destroying an infective agent(e.g., an HIV virus).

By “immunodeficiency virus” is meant a retrovirus that, in wild-typeform, is capable of infecting T4 cells of a primate host and possesses aviral morphogenesis and morphology characteristic of the lentivirussubfamily. The term includes, without limitation, all variants of HIVand SIV, including HIV-1, HIV-2, SIVmac, SIVagm, SIVmnd, SIVsmm, SIVman,SIVmand, and SIVcpz.

By “MHC-independent” is meant that the cellular cytolytic response doesnot require the presence of an MHC class II antigen on the surface ofthe targeted cell.

By a “functional cytolytic signal-transducing derivative” is meant afunctional derivative (as defined above) which is capable of directingat least 40%, more preferably 70%, or most preferably at least 90% ofthe biological activity of the wild type molecule. As used herein, a“functional cytolytic signal-transducing derivative” may act by directlysignaling the therapeutic cell to destroy a receptor-bound agent or cell(e.g., in the case of an intracellular chimeric receptor portion) or mayact indirectly by promoting oligomerization with cytolytic signaltransducing proteins of the therapeutic cell (e.g., in the case of atransmembrane domain). Such derivatives may be tested for efficacy,e.g., using the in vitro assays described herein.

By a “functional HIV envelope-binding derivative” is meant a functionalderivative (as defined above) which is capable of binding any HIVenvelope protein. Functional derivatives may be identified using, e.g.,the in vitro assays described herein.

THERAPEUTIC ADMINISTRATION

The transformed cells of the present invention are used forimmunodeficiency virus therapy. Current methods of administering suchtransformed cells involve adoptive immunotherapy or cell-transfertherapy. These methods allow the return of the transformed immune-systemcells to the bloodstream. Rosenberg, Sci. Am. 62 (May 1990); Rosenberget al., N. Engl. J. Med. 323:570 (1990).

The pharmaceutical compositions of the invention may be administered toany animal which may experience the beneficial effects of the compoundsof the invention. Foremost among such animals are humans, although theinvention is not intended to be so limited.

DETAILED DESCRIPTION

The drawings will first be described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A presents the amino acid sequence about the site of fusionbetween CD4 (residues 1-369) and different receptor chains (SEQ ID NO:38-41). The underlined sequence shows the position of the amino acidsencoded within the BamHI site used for fusion construction. Thebeginning of the transmembrane domain is marked with a vertical bar. Theη sequence is identical to the ζ sequence at the amino terminus, butdiverges at the carboxyl terminus (Jin et al., Proc. Natl. Acad. Sci.USA 87:3319-3323 (1990)). FIG. 1B presents flow cytometric analysis ofsurface expression of CD4, CD4:ζ, CD4:γ and CD4:η in CV1 cells. Cellswere infected with virus expressing CD4 chimeras or CD16_(PI), incubatedfor 9 hours at 37° C., and stained with phycoerythrin-conjugatedanti-CD4 MAb Leu3A.

FIG. 2 shows surface expression of CD16_(TM) following coinfection ofCD16_(TM) alone (dense dots), or coinfected with virus expressing CD4:γ(dashes) or CD4:ζ (solid line). Sparse dots, cells infected with CD4:ζalone, stained with 3G8 (Fleit et al., Proc. Natl. Acad. Sci. USA79:3275-3279 (1982)) (anti-CD16 MAb).

FIG. 3 shows surface expression of CD16_(TM) following coinfection byviruses expressing CD16_(TM) and the following ζ chimeras: CD4:ζ (thickline), CD4:ζ C11G (solid line); CD4:ζ (dashed line); CD4:ζ C11G/D15G(dense dots); no coinfection (CD16_(TM) alone, sparse dots). Cells wereincubated with anti-CD16 MAb 3G8 and phycoerythrin-conjugated Fab′₂ goatantibodies to mouse IgG. The level of expression of the ζ chimeras wasessentially identical for the different mutants analyzed, andcoinfection of cells with viruses expressing CD16_(TM) and ζ chimerasdid not appreciably alter surface expression of the chimeras.

FIGS. 4A-D shows increased intracellular free calcium ion followscrosslinking of mutant ζ chimeras in a T cell line. Jurkat E6 cells(Weiss et al., J. Immunol. 133:123-128 (1984)) were infected withrecombinant vaccinia viruses and analyzed by flow cytometry. The resultsshown are for the gated CD4⁺ population, so that only cells expressingthe relevant chimeric protein are analyzed. The mean ratio of violet toblue Indo-1 fluorescence reflects the intracellular free calciumconcentration in the population as a whole and the percentage ofresponding cells reflects the fraction of cells which exceed apredetermined threshold ratio (set so that 10% of untreated cells arepositive). FIG. 4A and FIG. 4B show Jurkat cells expressing CD4:ζ (solidline) or CD16:ζ (dashed line) which were exposed to anti-CD4 MAb Leu3a(phycoerythrin conjugate), followed by crosslinking with goat antibodyto mouse IgG. The dotted line shows the response of uninfected cells toanti-CD3 MAb OKT3. FIGS. 4C and 4D show Jurkat cells expressing CD4:ζD15G (solid line); CD4:ζ C11G/D15G (dashes); or CD4;ζ C11G (dots) whichwere treated and analyzed as in FIGS. 4A and 4B.

FIGS. 5A-C shows that CD4:ζ, CD4:η, and CD4:γ receptors allow cytolyticT lymphocytes (CTL) to kill targets expressing HIV-1 gp120/41. FIG. 5A:solid circles, CTL expressing CD4:ζ incubated with HeLa cells expressinggp120/41; open circles, CTL expressing CD4:ζ incubated with uninfectedHeLa cells; solid squares, uninfected CTL incubated with HeLa cellsexpressing gp120/41; open squares, uninfected CTL incubated withuninfected HeLa cells. FIG. 5B: solid circles, CTL expressing CD4:ηincubated with HeLa cells expressing gp120/41; open circles, CTLexpressing CD4:γ incubated with HeLa cells expressing gp120/41; opensquares, CTL expressing the C11G/D15G double mutant CD4:ζ chimeraincubated with HeLa cells expressing gp120/41. FIG. 5C: Flow cytometricanalysis of CD4 expression by the CTL used in FIG. 5B. To correct thetarget to effector ratios the percent of cells expressing CD4 chimerawas determined by subtracting the scaled negative (uninfected)population by histogram superposition; for comparative purposes in thisfigure the uninfected cells were assigned an arbitrary threshold whichgives roughly the same fraction positive for the other cell populationsas would histogram subtraction.

FIGS. 6A-B shows specificity of CD4-directed cytolysis. FIG. 6A: solidcircles, CTL expressing CD4:ζ incubated with HeLa cells expressingCD16_(PI); open circles, CTL expressing CD4 incubated with HeLa cellsexpressing gp120; solid squares, CTL expressing CD16:ζ incubated withHeLa cells expressing gp120/41; open squares, CTL expressing CD16_(PI)incubated with HeLa cells expressing gp120/41. FIG. 6B: solid circles,CTL expressing CD4:ζ incubated with Raji (MHC class II⁺) cells; opencircles, uninfected CTL cells incubated with RJ2.2.5 (MHC class II⁻ Rajimutant) cells; solid squares, uninfected CTL incubated with Raji (MHCclass II⁺) cells; open squares, CTL expressing CD4:ζ incubated withRJ2.2.5 (MHC class II⁻) cells. The ordinate scale is expanded.

FIGS. 7A-B shows characterization of the CD16:ζ chimeric receptor. FIG.7A is a schematic diagram of the CD16:ζ fusion protein. Theextracellular portion of the phosphatidylinositol-linked form ofmonomeric CD16 was joined to dimeric ζ just external to thetransmembrane domain. The protein sequence at the fusion junction isshown at the bottom (SEQ ID NO:42,43). FIG. 7B shows a flow cytometricanalysis of calcium mobilization following crosslinking of the CD16:ζchimera in either a TCR positive or TCR negative cell line. The meanratio of violet to blue fluorescence (a measure of relative calcium ionconcentration) among cell populations treated with antibodies at time 0is shown. Solid squares, the response of Jurkat cells to anti-CD3 MAbOKT3; solid triangles, the response of CD16:ζ to anti-CD16 MAb 3G8crosslinking in the REX33A TCR⁻ mutant; open squares, the response toCD16:ζ crosslinking in the Jurkat TCR⁻ mutant line JRT3.T3.5; opentriangles, the response to CD16:ζ crosslinking in Jurkat cells; crosses,the response to nonchimeric CD16 in Jurkat cells; and dots, the responseto nonchimeric CD16 in the REX33A TCR⁻ cell line.

FIGS. 8A-B shows deletion analysis of cytolytic potential. FIG. 8A showsthe locations of the ζ deletion endpoints. Here as elsewhere mutationsin ζ are represented by the original residue-location-mutant residueconvention, so that D66*, for example, denotes replacement of Asp-66 bya termination codon. FIG. 8B shows cytolysis assay results of undeletedCD16:ζ and salient ζ deletions. Hybridoma cells expressing surfaceantibody to CD16 were loaded with ⁵¹Cr and incubated with increasingnumbers of human cytolytic lymphocytes (CTL) infected with vacciniarecombinants expressing CD16:ζ chimeras. The percent of ⁵¹Cr released isplotted as a function of the effector (CTL) to target (hybridoma) cellratio (e/t). Solid circles, cytolysis mediated by cells expressingCD16:ζ (mfi 18.7); solid squares, cytolysis mediated by cells expressingCD16:ζ Asp66* (mfi 940.2); open squares, cytolysis mediated by cellsexpressing CD16:ζ Glu60* (mfi 16.0); open circles, cytolysis mediated bycells expressing CD16:ζ Tyr51* (mfi 17.4); solid triangles, cytolysismediated by cells expressing CD16:ζ Phe34* (mfi 17.8); and opentriangles, cytolysis mediated by cells expressing nonchimeric CD16 (mfi591). Although in this experiment the expression of CD16:ζ Asp66* wasnot matched to that of the other fusion proteins, cytolysis by cellsexpressing CD16:ζ at equivalent levels in the same experiment gaveresults essentially identical to those shown by cells expressing CD16:ζAsp66.

FIGS. 9A-D shows that elimination of the potential for transmembraneinteractions reveals a short ζ segment capable of mediating cytolysis.FIG. 9A is a schematic diagram of the monomeric bipartite and tripartitechimeras. At the top is the CD16:ζ construct truncated at residue 65 andlacking transmembrane Cys and Asp residues. Below are the CD16:CD5:ζ andCD16:CD7:ζ constructs and related controls. The peptide sequences of theintracellular domains are shown below (SEQ ID NO:45-47). FIG. 9B showsthe cytolytic activity of monomeric chimera deletion mutants. Thecytolytic activity of cells expressing CD16:ζ (solid circles; mfi 495)was compared to that of cells expressing CD16:ζ Asp66* (solid squares;mfi 527) or the mutants CD16:ζ Cys11Gly/Asp15Gly/Asp66*, (open squares;mfi 338) and CD16:ζ Cys11Gly/Asp15Gly/Glu60* (filled triangles; mfi259). FIG. 9C shows the cytolytic activity mediated by tripartite fusionproteins. Solid triangles, CD16:ζ Asp66*; open squares, CD16:5:ζ(48-65); solid squares CD16:7:ζ (48-65); open triangles, CD16:7:ζ(48-59); open circles, CD16:5; solid circles, CD16:7. FIG. 9D showscalcium mobilization by mutant and tripartite chimeras in the TCRnegative Jurkat JRT3.T3.5 mutant cell line. Open circles, response ofcells expressing dimeric CD16:ζ Asp66*; solid squares, response of cellsexpressing CD16:ζ Cys11Gly/Asp15Gly/Asp66*; open squares, response ofcells expressing CD16:ζ Cys11Gly/Asp15Gly/Glu60*; solid triangles,response of cells expressing CD16:7:ζ (48-65); and open triangles,response of cells expressing CD16:ζ (48-59).

FIGS. 10A-F shows the contribution of individual amino acids to theactivity of the 18 residue cytolytic signal-transducing motif. FIGS. 10Aand 10B show cytolytic activity and FIG. 10C shows calcium ionmobilization mediated by chimeras bearing point mutations near thecarboxyl terminal tyrosine (Y62). FIGS. 10A and 10B represent datacollected on cells expressing low and high amounts, respectively, of theCD16:ζ fusion proteins. Identical symbols are used for the calciummobilization and cytolysis assays, and are shown in one letter code atright. Solid circles, cells expressing CD16:ζ (mfi in A, 21; B, 376);solid squares, cells expressing CD16:7:ζ (48-65) (mfi A, 31; B, 82);open squares, CD16:7:ζ (48-65)Glu60Gln (mfi A, 33; B, 92), crosses,CD16:7:ζ (48-65)Asp63Asn (mfi A, 30; B, 74); solid triangles, CD16:7:ζ(48-65)Tyr62Phe (mfi A, 24; B, 88); open circles, CD16:7:ζ(48-65)Glu61Gln (mfi A, 20; B, 62); and open triangles, CD16:7:ζ(48-65)Tyr62Ser (mfi B, 64). FIGS. 10D and 10E show cytolytic activityand FIG. 10F shows calcium ion mobilization by chimeras bearing pointmutations near the amino terminal tyrosine (Y51). Identical symbols areused for the calcium mobilization and cytolysis assays and are shown atright. Solid circles, cells expressing CD16:ζ (mfi in D, 21.2; in E,672); solid squares, cells expressing CD16:7:ζ (48-65) (mfi D, 31.3; E,179); solid triangles, CD16:7:ζ (48-65)Asn48Ser (mfi D, 22.4; E, 209);open squares, CD16:7:ζ (48-65)Leu5oSer (mfi D, 25.0; E, 142); and opentriangles, CD16:7:ζ (48-65)Tyr51Phe (mfi D, 32.3; E, 294).

FIGS. 11A-B shows alignment of internal repeats of ζ and comparison oftheir ability to support cytolysis. FIG. 11A is a schematic diagram ofchimeras formed by dividing the ζ intracellular domain into thirds andappending them to the transmembrane domain of a CD16:7 chimera. Thesequences of the intracellular domains are shown below (SEQ IDNO:48-50), with shared residues boxed, and related residues denoted byasterisks. FIG. 11B shows the cytolytic potency of the three ζsubdomains. Solid circles, cells expressing CD16:ζ (mfi 476); solidsquares, CD16:7:ζ (33-65) (mfi 68); open squares, CD16:7:ζ (71-104) (mfi114); and solid triangles, CD16:7:ζ (104-138) (mfi 104).

FIG. 12 is a schematic diagram of the CD16:FcRγII chimeras.

FIGS. 13A-B shows calcium mobilization following crosslinking ofCD4:FcRγII and CD16:FcRγII chimeras. FIG. 13A shows the ratio of violetto blue fluorescence emitted by cells loaded with the calcium sensitivefluorophore Indo-1 shown as a function of time following crosslinking ofthe CD16 extracellular domain with antibodies. FIG. 13B shows a similaranalysis of the increase in ratio of violet to blue fluorescence ofcells bearing CD4:FcRγII chimeras, following crosslinking withantibodies.

FIGS. 14A-B shows cytolysis assays of CD4:FcRγII and CD16:FcRγIIchimeras. FIG. 14A shows the percent of ⁵¹Cr released from anti-CD16hybridoma (target) cells when the cells are exposed to increasingnumbers of cytotoxic T lymphocytes expressing CD16:FcRγII chimeras(effector cells). FIG. 14B shows a similar analysis of cytotoxicitymediated by CD4:FcRγII chimeras against target cells expressing HIVenvelope glycoproteins.

FIGS. 15A-E shows identification of residues in the FcRγII A tail whichare important for cytolysis. FIG. 15A is a schematic diagram of thedeletion constructs. FIGS. 15B and 15C shows calcium mobilization andcytolysis by carboxyl-terminal deletion variants of CD16:FcRγII A. FIGS.15D and 15E show calcium mobilization and cytolysis by tripartitechimeras bearing progressively less of the amino terminus of theintracellular tail of CD16:FcRγII A.

FIG. 16 (SEQ ID NO: 24) shows the amino acid sequence of the CD3 deltareceptor protein; the boxed sequence represents a preferred cytolyticsignal transducing portion.

FIG. 17 (SEQ ID NO: 25) shows the amino acid sequence of the T3 gammareceptor protein; the boxed sequence represents a preferred cytolyticsignal transducing portion.

FIG. 18 (SEQ ID NO: 26) shows the amino acid sequence of the mb1receptor protein; the boxed sequence represents a preferred cytolyticsignal transducing portion.

FIG. 19 (SEQ ID NO: 27) shows the amino acid sequence of the B29receptor protein; the boxed sequence represents a preferred cytolyticsignal transducing portion.

FIG. 20 shows a schematic diagram of the CD4 chimeras. Molecule “A” isCD4(D1-D4):Ig:CD7; molecule “B” is CD4(D1,D2):Ig:CD7; molecule “C” isCD4(D1-D4):Ig:CD7:ζ; molecule “D” is CD4(D1,D2):Ig:CD7:ζ; and molecule“E” is CD4:ζ. The extracellular domain of the human CD4 moleculecorresponding to amino acids 1-394 of the precursor was joined by aBamHI site to the hinge, CH1, and CH2 domains of human IgG1 as describedpreviously (Zettlmeissl et al., DNA Cell Biol. 9:347 (1990)) except thata cDNA version of the human Ig sequences was used to allow expression invaccinia virus recombinants. The two-domain version of the CD4 chimeraswere created by insertion of a BamHI adaptor at the unique NheI site(corresponding to amino acid 200) in the CD4 precursor cDNA. Themembrane attachment sequences consisted of 22 residues from the firstexon of human membrane-bound IgG1 followed by CD7 residues 146-203.Amino acids 55 through 163 of ζ served as the trigger motif of thetetrapartite constructs (C and D). In tetrapartite constructs containingthe ζ chain, intracellular expression of ζ was documented with acommercially available antibody against the intracellular domain(Coulter).

FIG. 21 shows cytolysis of target cells expressing the HIV-1 envelopeglycoprotein mediated by the cytotoxic T-cell clone, WH3, expressingvarious CD4-derived chimeras as effector molecules. For cytotoxicityassays, the human CD8⁺ CD4⁻ HLA B44 restricted T cell line, WH3, wasmaintained in IMDM supplemented with 10% human serum as previouslydescribed herein. The cells were stimulated with gamma-irradiated (3000rad) B44-bearing mononuclear cells and phytohemagglutinin (PHA) at 1μg/ml. After one day of stimulation, the PHA was diluted to 0.5 μg/ml byaddition of fresh medium; after 3 days the medium was changedcompletely. Cells were grown for at least 10 days before use incytotoxicity assays. Cells were infected with the appropriaterecombinant vaccinia viruses as described herein for vPE16. Infectionswere allowed to proceed for an additional 3-4 hours in complete mediumafter which cells were harvested by centrifugation and resuspended at adensity of 1×10⁷/ml. 100 μl were added to each well of a U-bottommicrotiter plate containing 100 μl per well of complete medium anddiluted in 2-fold serial steps. Two wells for each sample did notcontain lymphocytes, to allow spontaneous chromium release and totalchromium uptake to be measured. The target cells, HeLa subline S3(HeLa-S3, ATCC) were infected as above in 10 cm dishes with vPE16. 10⁶infected cells were detached with PBS and 1 mM EDTA, centrifuged andresuspended in 100 μl of ¹⁵Cr sodium chromate (1 mCi/ml in PBS) for 1hour at 37° C. and then washed three times with PBS. 100 μl of labelledtarget cells were added to each well. The microtiter plate was spun at750×g for 1 minute and incubated for 4 hours at 37° C. At the end of theincubation period, the cells in each well were resuspended by gentlepipetting, a sample removed to determine the total counts incorporatedand the microtiter plate was spun at 750×g for 1 min. Aliquots (100 μl)of the supernatant were removed and counted in a gamma ray scintillationcounter. The effector:target ratio was corrected for the percent ofcells infected as measured by flow cytometry.

FIG. 22 shows replication of HIV-1 in transfectant cell lines. Celllines stably expressing wild type CD4 and various recombinant chimeraswere established in a subline of the human embryonal kidney cell line293. A virus stock of the HIV-1 IIIB isolate was prepared with a titerof ≈10⁶ infectious particles/ml as measured by end-point dilutionanalysis using the human T-cell line C8166 as an indicator. Infectionswere carried out at an approximate MOI of 1 for a period of 8-12 hoursat 37° C. On the following day the cells were washed with PBS threetimes, trypsinized, replated in new dishes and the culture supernatantsampled for p24 titer (designated day 0). At 3-4 day intervalsthereafter, cell culture supernatants were collected and retained forp24 analysis. The cells were resupplied with fresh medium containinghygromycin B at a concentration of 100 μg/ml. Analysis of culturesupernatants was carried out using a commercial ELISA-based HIV-1 p24antigen assay kit (Coulter) according to the instructions supplied bythe manufacturer. Results are representative of two independentexperiments of similar duration.

FIG. 23 shows the nucleic acid (SEQ ID NO:28) and amino acid (SEQ IDNO:29) sequence of the D1-D4 domains of CD4 (CD4 Ban).

FIG. 24 shows the nucleic acid (SEQ ID NO:30) and amino acid (SEQ IDNO:31) sequence of the D1-D2 domains of CD4 (CD4 Nhe).

FIG. 25 shows the nucleic acid (SEQ ID NO:32) and amino acids (SEQ IDNO:33) sequence of the hinge, CH2, and CH3 domains of human IgG1 (Igh23Bam).

FIG. 26 shows the nucleic acid (SEQ ID NO:34) and amino acid (SEQ IDNO:35) sequence of the transmembrane domain of CD7 (TM7 Bam Mlu).

FIG. 27 shows the nucleic acid (SEQ ID NO:36) and amino acid (SEQ IDNO:37) sequence of the intracellular domain of zeta (Zeta Mlu Not).

FIG. 28 shows the DNA sequence (SEQ ID NO:51) and primary amino acidsequence (SEQ ID NO:52) of a synthetic alpha helix.

EXAM

PLE I

Construction of Human IgG1:Receptor Chimeras

Human IgG1 heavy chain sequences were prepared by joining sequences inthe C_(H)3 domain to a cDNA fragment derived from the 3′ end of thetransmembrane form of the antibody mRNA. The 3′ end fragment wasobtained by polymerase chain reaction using a tonsil cDNA library assubstrate, and oligonucleotides having the sequences:

CGC GGG GTG ACC GTG CCC TCC AGC AGC TTG GGC (SEQ ID NO: 7) and

CGC GGG GAT CCG TCG TCC AGA GCC CGT CCA GCT CCC CGT CCT GGG CCT CA (SEQID NO: 8),

corresponding to the 5′ and 3′ ends of the desired DNA fragmentsrespectively. The 5′ oligo is complementary to a site in the CH1 domainof human IgG1, and the 3′ oligo is complementary to a site just 5′ ofthe sequences encoding the membrane spanning domain. The PCR product wasdigested with BstXI and BamHI and ligated between BstXI and BamHI sitesof a semisynthetic IgG1 antibody gene bearing variable and constantregions. Following the insertion of the BstXI to BamHI fragment, theamplified portions of the construct were replaced up to the SmaI site inC_(H) ³ by restriction fragment interchange, so that only the portionbetween the SmaI site and the 3′ oligo was derived from the PCRreaction.

To create a human IgG1:ζ chimeric receptor, the heavy chain gene endingin a BamHI site was joined to the BamHI site of the ζ chimera describedbelow, so that the antibody sequences formed the extracellular portion.Flow cytometry of COS cells transfected with a plasmid encoding thechimera showed high level expression of antibody determinants when anexpression plasmid encoding a light chain cDNA was cotransfected, andmodest expression of antibody determinants when the light chainexpression plasmid was absent.

Similar chimeras including human IgG1 fused to η or γ (see below), orany signal-transducing portion of a T cell receptor or Fc receptorprotein may be constructed generally as described above using standardtechniques of molecular biology.

To create a single transcription unit which would allow both heavy andlight chains to be expressed from a single promoter, a plasmid encodinga bicistronic MRNA was created from heavy and light chain codingsequences, and the 5′ untranslated portion of the MRNA encoding the 78kD glucose regulated protein, otherwise known as grp78, or BiP. grp78sequences were obtained by PCR of human genomic DNA using primers havingthe sequences:

CGC GGG CGG CCG CGA CGC CGG CCA AGA CAG CAC (SEQ ID NO: 9) and

CGC GTT GAC GAG CAG CCA GTT GGG CAG CAG CAG (SEQ ID NO: 10)

at the 5′ and 3′ ends respectively. Polymerase chain reactions withthese oligos were performed in the presence of 10% dimethyl sulfoxide.The fragment obtained by PCR was digested with NotI and HincII andinserted between NotI and HpaI sites downstream from human IgG1 codingsequences. Sequences encoding a human IgG kappa light chain cDNA werethen inserted downstream from the grp78 leader, using the HincII siteand another site in the vector. The expression plasmid resulting fromthese manipulations consisted of the semisynthetic heavy chain gene,followed by the grp78 leader sequences, followed by the kappa lightchain cDNA sequences, followed by polyadenylation signals derived froman SV40 DNA fragment. Transfection of COS cells with the expressionplasmid gave markedly improved expression of heavy chain determinants,compared to transfection of plasmid encoding heavy chain determinantsalone.

To create a bicistronic gene comprising a heavy chain/receptor chimeraand a light chain, the upstream heavy chain sequences can be replaced byany chimeric heavy chain/ receptor gene described herein.

EXAMPLE II Construction of CD4 Receptor Chimeras

Human ζ (Weissman et al., Proc. Natl. Acad. Sci. USA 85:9709-9713(1988b)) and γ (Kuster et al., J. Biol. Chem. 265:6448-6452 (1990))cDNAs were isolated by polymerase chain reaction from libraries preparedfrom the HPB-ALL tumor cell line (Aruffo et al., Proc. Natl. Acad. Sci.USA 84:8573-8577 (1987b)) and from human natural killer cells, while ηcDNA (Jin et al., Proc. Natl. Acad. Sci. USA 87:3319-3323 (1990)) wasisolated from a murine thymocyte library. ζ, η and γ cDNAs were joinedto the extracellular domain of an engineered form of CD4 possessing aBamHI site just upstream of the membrane spanning domain (Aruffo et al.,Proc. Natl. Acad. Sci. USA 84:8573-8577 (1987b); Zettlmeissl et al., DNACell Biol. 9347-353 (1990)) which was joined to the BamHI site naturallypresent in the ζ and η cDNAs at a similar location a few residuesupstream of the membrane spanning domain (SEQ ID NOS: 1, 3, 4 and 6). Toform the fusion protein with γ a BamHI site was engineered into thesequence at the same approximate location (FIG. 1; SEQ ID NO: 2 and 5).The gene fusions were introduced into a vaccinia virus expressionplasmid bearing the E. coli gpt gene as a selectable marker, andinserted into the genome of the vaccinia WR strain by homologousrecombination and selection for growth in mycophenolic acid (Falkner etal., J. Virol. 62:1849-1854 (1988); Boyle et al., Gene 65:123-128(1988)). Flow cytometric analysis showed that the vaccinia recombinantsdirect the abundant production of CD4:ζ and CD4:γ fusion proteins at thecell surface, whereas the expression of CD4:η is substantially weaker(FIG. 1B). The latter finding is consistent with a recent report thattransfection of an η cDNA expression plasmid into a murine hybridomacell line gave substantially less expression than transfection of acomparable ζ expression plasmid (Clayton et al., J. Exp. Med.172:1243-1253 (1990)). Immunoprecipitation of cells infected with thevaccinia recombinants revealed that the fusion proteins form covalentdimers, unlike the naturally occurring CD4 antigen. The molecular massesof the monomeric CD4:ζ and CD4:γ fusion proteins and native CD4 werefound to be 63, 55 and 53 kD respectively. The larger masses of thefusion proteins are approximately consistent with the greater length ofthe intracellular portion, which exceeds that of native CD4 by 75 (CD4:ζor 5 (CD4:γ) residues.

EXAMPLE III CD4 Chimeras Can Associate With Other Receptor Chains

Cell surface expression of the macrophage/natural killer cell form ofhuman FcγRIII (CD16_(TM)) on transfectants is facilitated bycotransfection with murine (Kurosaki et al., Nature 342:805-807 (1989))or human (Hibbs et al., Science 246:1608-1611 (1989)) γ, as well as byhuman ζ (Lanier et al., Nature 342:803-805 (1989)).

Consistent with these reports, expression of the chimeras also allowedsurface expression of CD16_(TM) when delivered to the target cell eitherby cotransfection or by coinfection with recombinant vaccinia viruses(FIG. 2). The promotion of CD16_(TM) surface expression by ζ was morepronounced than promotion by γ (FIG. 2) in the cell lines examined,whereas native CD4 did not enhance CD16_(TM) surface expression.

EXAMPLE IV Asp ζ Mutants Do Not Coassociate with Fc Receptor

To create chimeras which would not associate with existing antigen or Fcreceptors, mutant ζ fusion proteins which lacked either theintramembranous Asp or intramembranous Cys residue or both wereprepared. Flow cytometry showed that the intensity of cell surfaceexpression by the different mutant chimeras was not appreciablydifferent from the unmutated precursor, and immunoprecipitationexperiments showed that total expression by the chimeras was similar. Asexpected, the mutant chimeras lacking the transmembrane cysteine residuewere found not to form disulfide linked dimers. The two mutant chimeraslacking Asp were incapable of supporting the surface expression ofCD16^(TM), whereas the monomeric chimeras lacking Cys but bearing Aspallowed CD16_(TM) to be coexpressed, but at lower efficiency than theparental dimer (FIG. 3).

EXAMPLE V Mutant Receptors Retain the Ability to Initiate a CalciumResponse

To determine whether crosslinking of the fusion proteins would allow theaccumulation of free intracellular calcium in a manner similar to thatknown to occur with the T cell antigen receptor, cells of the human Tcell leukemia line, Jurkat E6 (ATCC Accessior Number TIB 152, AmericanType Culture Collection, Rockville, Md.), were infected with thevaccinia recombinants and the relative cytoplasmic calcium concentrationfollowing crosslinking of the extracellular domain with antibodies wasmeasured. Flow cytometric measurements were performed with cells loadedwith the calcium sensitive dye Indo-1 (Grynkiewicz et al., J. Biol.Chem. 260:3340-3450 (1985); Rabinovitch et al., J. Immunol. 137:952-961(1986)). FIGS. 4A-D shows the results of calcium flux experiments withcells infected with CD4:ζ and the Asp⁻ and Cys⁻ mutants of ζ.Crosslinking of the chimeras, reproducibly increased intracellularcalcium. CD4:η and CD4:γ similarly allowed accumulation intracellularcalcium in infected cells. Jurkat cells express low levels of CD4 on thecell surface, however, crosslinking of the native CD4 in the presence orabsence of CD16:ζ does not alter intracellular calcium levels (FIGS.4A-B).

EXAMPLE VI CD4:ζ, η, and γ Chimeras Mediate Cytolysis of TargetsExpressing HIV gp120/41

To determine whether the chimeric receptors would trigger cytolyticeffector programs, a model target:effector system based on CD4recognition of the HIV envelope gp120/gp41 complex was created. HeLacells were infected with recombinant vaccinia viruses expressinggp120/gp41 (Chakrabarti et al., Nature 320:535-537 (1986); Earl et al.,J. Virol. 64:2448-2451 (1990)) and labeled with ⁵¹Cr. The labeled cellswere incubated with cells from a human allospecific (CD8⁺, CD4⁻)cytotoxic T lymphocyte line which had been infected with vacciniarecombinants expressing the CD4:ζ, CD4:η, or CD4:γ chimeras, or theCD4:ζ Cys11Gly:Asp15Gly double mutant chimera. FIGS. 5A-C shows thatHeLa cells expressing gp120/41 were specifically lysed by cytotoxic Tlymphocytes (CTL) expressing CD4 chimeras. Uninfected HeLa cells werenot targeted by CTL armed with CD4:ζ chimeras, and HeLa cells expressinggp120/41 were not recognized by uninfected CTL. To compare the efficacyof the various chimeras, the effector to target ratios were correctedfor the fraction of CTL expressing CD4 chimeras, and for the fraction ofHeLa cells expressing gp120/41, as measured by flow cytometry. FIG. 5Cshows a cytometric analysis of CD4 expression by the CTL used in thecytolysis experiment shown in FIGS. 5A and 5B. Although the mean densityof surface CD4:ζ greatly exceeded the mean density of CD4:η, thecytolytic efficiencies of cells expressing either form were similar.Correcting for the fraction of targets expressing gp120 , the efficiencyof cytolysis mediated by CD4:ζ and CD4:η proteins are comparable to thebest efficiencies reported for specific T cell receptor target:effectorpairs (the mean effector to target ratio for 50% release by T cellsexpressing CD4:ζ was 1.9±0.99, n=10. The CD4:γ fusion was less active,as was the CD4:ζ fusion lacking the transmembrane Asp and Cys residues.However in both cases significant cytolysis was observed (FIGS. 5B-C).

To control for the possibility that vaccinia infection might promoteartefactual recognition by CTL, similar cytolysis experiments wereperformed with target cells infected with vaccinia recombinantsexpressing the phosphatidylinositol linked form of CD16 (CD16_(PI)) andlabeled with ⁵¹Cr, and with CTL infected with control recombinantsexpressing either CD16_(PI) or CD16:ζ. FIG. 6A shows that T cellsexpressing non-CD4 chimeras do not recognize native HeLa cells or HeLacells expressing gp120/41, and similarly that T cells expressing CD4chimeras do not recognize HeLa cells expressing other vaccinia-encodedsurface proteins. In addition, CTLs expressing non-chimeric CD4 do notsignificantly lyse HeLa cells expressing gp120/41 (FIG. 6A).

EXAMPLE VII MHC Class II-Bearing Cells Are Not Targeted by the Chimeras

CD4 is thought to interact with a nonpolymorphic sequence expressed byMHC class II antigen (Gay et al., Nature 328:626-629 (1987); Sleckman etal., Nature 328:351-353 (1987)). Although a specific interaction betweenCD4 and class II antigen has never been documented with purifiedproteins, under certain conditions adhesion between cells expressing CD4and cells expressing class II molecules can be demonstrated (Doyle etal., Nature 330:256-259 (1987); Clayton et al., J. Exp. Med.172:1243-1253 (1990); Lamarre et al., Science 245:743-746 (1989)). Nextexamined was whether killing could be detected against cells bearingclass II. FIG. 6B shows that there is no specific cytolysis directed byCD4:ζ against the Raji B cell line, which expresses abundant class IIantigen. Although a modest (≈5%) cytolysis is observed, a classII-negative mutant of Raji, RJ2.2.5, (Accolla, J. Exp. Med.157:1053-1058 (1983)) shows a similar susceptibility, as do Raji cellsincubated with uninfected T cells.

EXAMPLE VIII Sequence Requirements for Induction of Cytolysis by the TCell Antigen/Fc Receptor Zeta Chain

Although chimeras between CD4 and ζ can arm cytotoxic T lymphocytes(CTL) to kill target cells expressing HIV gp120, an alternative to CD4was sought in order to unambiguously compare the properties of zetachimeras introduced into human T cell lines. Such lines can express CD4,making it difficult to specifically define the relationship between thetype or degree of calcium mobilization and the cytotoxic potential ofthe different chimeras. To circumvent this, chimeras were createdbetween ζ and CD16 in which the extracellular domain of CD16 is attachedto the transmembrane and intracellular sequences of ζ (FIG. 7A). Thegene fusions were introduced into a vaccinia virus expression plasmidbearing the E. coli gpt gene as a selectable marker and inserted intothe genome of the vaccinia WR strain by homologous recombination andselection for growth in mycophenolic acid (Falkner and Moss, J. Virol.62:1849 (1988); Boyle and Coupar, Gene 65:123 (1988)).

T cell lines were infected with the vaccinia recombinants and therelative cytoplasmic free calcium ion concentration was measuredfollowing crosslinking of the extracellular domains with antibodies.Both spectrofluorimetric (bulk population) and flow cytometric (singlecell) measurements were performed with cells loaded with the dye Indo-1(Grynkiewicz et al., J. Biol. Chem. 260:3440 (1985); Rabinovitch et al.,J. Immunol. 137:952 (1986)). FIG. 7B shows an analysis of data collectedfrom cells of the Jurkat human T cell leukemia line infected withvaccinia recombinants expressing CD16:ζ fusion protein. Crosslinking ofthe chimeras reproducibly increased intracellular calcium, while similartreatment of cells expressing nonchimeric CD16 had little or no effect.When the chimera was expressed in mutant cell lines lacking antigenreceptor, either REX33A (Breitmeyer et al., J. Immunol. 138:726 (1987);Sancho et al., J. Biol. Chem 264:20760 (1989)), or Jurkat mutantJRT3.T3.5 (Weiss et al., J. Immunol. 135:123 (1984)); or a strongresponse to CD16 antibody crosslinking was seen. Similar data have beencollected on the REX20A (Breitmeyer et al., supra, 1987; Blumberg etal., J. Biol. Chem. 265:14036 (1990)) mutant cell line, and a CD3/Tinegative mutant of the Jurkat cell line established in this laboratory.Infection with recombinants expressing CD16:ζ did not restore theresponse to anti-CD3 antibody, showing that the fusion protein did notact by rescuing intracellular CD3 complex chains.

To evaluate the ability of the chimeras to redirect cell-mediatedimmunity, CTLs were infected with vaccinia recombinants expressing CD16chimeras and used to specifically lyse hybridoma cells expressingmembrane-bound anti-CD16 antibodies. This assay is an extension of ahybridoma cytotoxicity assay originally developed to analyze effectormechanisms of cells bearing Fc receptors (Graziano and Fanger, J.Immunol. 138:945, 1987; Graziano and Fanger, J. Immunol. 139:35-36,1987; Shen et al., Mol. Immunol. 26:959, 1989; Fanger et al., Immunol.Today 10: 92, 1989). FIG. 8B shows that expression of CD16:ζ incytotoxic T lymphocytes allows the armed CTL to kill 3G8 (anti-CD16;Fleit et al., Proc. Natl. Acad. Sci. USA 79:3275, 1982) hybridoma cells,whereas CTL expressing the phosphatidylinositol-linked form of CD16 areinactive. CTL armed with CD16:ζ also do not kill hybridoma cellsexpressing an irrelevant antibody.

To identify the minimal ζ sequences necessary for cytolysis, a series ofdeletion mutants were prepared in which successively more of the ζintracellular domain (SEQ ID NO:44) was removed from the carboxylterminus (FIG. 8A). Most of the intracellular domain of zeta could beremoved with little consequence for cytolytic potential; the full lengthchimera CD16:ζ was essentially equal in efficacy to the chimera deletedto residue 65, CD16:ζ Asp66* (FIG. 8B). A substantial decrease incytotoxicity was observed on deletion to ζ residue 59 (chimera CD16:ζGlu60*), and further deletion to residue 50 resulted in slightly lessactivity. However complete loss of activity was not observed even whenthe intracellular domain was reduced to a three residue transmembraneanchor (FIG. 8B).

Because ζ is a disulfide linked dimer, one explanation for the retentionof cytolytic activity was that endogenous ζ was forming heterodimerswith the chimeric ζ deletion, thereby reconstituting activity. To testthis idea, ζ residues 11 and 15 were changed from Asp and Cysrespectively to Gly (Cys11Gly/Asp15Gly), and immunoprecipitations werecarried out as follows. Approximately 2×10⁶ CV1 cells were infected forone hour in serum free DME medium with recombinant vaccinia at amultiplicity of infection (moi) of at least ten. Six to eight hourspost-infection, the cells were detached from the plates with PBS/1 mMEDTA and surface labeled with 0.2 mCi ¹²⁵I per 2×10⁶ cells usinglactoperoxidase and H₂O₂ by the method of Clark and Einfeld (LeukocyteTyping II, pp 155-167, Springer-Verlag, N.Y., 1986). The labeled cellswere collected by centrifugation and lysed in 1% NP-40, 0.1% SDS, 0.15MNaCl, 0.05M Tris, pH 8.0, 5 mM MgCl₂, 5 mM KCl, 0.2M iodoacetamide and 1mM PMSF. Nuclei were removed by centrifugation, and CD16 proteins wereimmunoprecipitated with antibody 3G8 (Fleit et al., supra, 1982;Medarex) and anti-mouse IgG agarose (Cappel, Durham, N.C.). Samples wereelectrophoresed through an 8% polyacrylamide/SDS gel under non-reducingconditions or through a 10% gel under reducing conditions. Theseimmunoprecipitations confirmed that the CD16:ζ Cys11Gly/Asp15Gly chimeradid not associate in disulfide-linked dimer structures.

The cytolytic activity of the mutant receptors was also tested. Themutated chimera deleted to residue 65 (CD16:ζ Cys11Gly/Asp15Gly/Asp66*)was, depending on the conditions of assay, two to eight fold less activein the cytolysis assay than the comparable unmutated chimera (CD16:ζAsp66*), which was usually within a factor of two of, orindistinguishable in activity from, CD16:ζ (FIG. 9B). The reduction inactivity of the mutant chimeras is comparable to the reduction seen withCD4 chimeras of similar structure (see above) and is most likelyattributable to the lower efficiency of ζ monomers compared to dimers.In contrast, the Asp⁻, Cys⁻ mutated chimera deleted to residue 59 had nocytolytic activity (FIG. 9B), supporting the hypothesis that associationwith other chains mediated by the transmembrane Cys and/or Asp residueswas responsible for the weak persistence of cytolytic activity indeletions more amino terminal than residue 65.

Flow cytometric studies showed that the deletion mutants lackingtransmembrane Asp and Cys residues could still promote an increase infree intracellular calcium ion in response to antibody crosslinking in aTCR⁻ mutant Jurkat cell line (FIG. 9D). Similar results were obtainedfor chimeras expressed in the parental Jurkat line. In the case ofCD16:ζ Cys11Gly/Asp15Gly/Glu60*, these data demonstrate that the abilityto mediate calcium responsiveness can be mutationally separated from theability to support cytolysis.

To definitively eliminate the possible contribution of ζ transmembraneresidues, the transmembrane and first 17 cytoplasmic residues of ζ werereplaced by sequences encoding the membrane spanning and first 14 orfirst 17 cytoplasmic residues of the CD5 or CD7 antigens, respectively(FIG. 9A). The resulting tripartite fusion proteins CD16:5:ζ (48-65) andCD16:7:ζ (48-65) did not form disulfide-linked dimers as do the simplerCD16:ζ chimeras, because they lacked the cysteine residue in the ζtransmembrane domain. Both tripartite chimeras were able to mobilizecalcium in Jurkat and TCR negative cell lines (FIG. 9D) and to mount acytolytic response in CTL (FIG. 9C and data not shown). Howevertruncation of the ζ portion to residue 59 in chimera CD16:7:ζ (48-59)abrogates the ability of tripartite fusion to direct calciumresponsiveness in TCR positive or negative Jurkat cells or cytolysis inmature CTL (FIGS. 9C and 9D and data not shown).

To examine the contributions of individual residues within the18-residue motif, we prepared a number of mutant variants bysite-directed mutagenesis, and evaluated their ability to mediatereceptor-directed killing under conditions of low (FIGS. 10A and 10D) orhigh (FIGS. 10B and 10E) expression of chimeric receptor. FIGS. 10A-Fshows that while a number of relatively conservative substitutions(i.e., replacing acidic residues with their cognate amides, or tyrosinewith phenylalanine) which spanned residues 59 to 63 yielded moderatecompromise of cytolytic efficacy, in general the variants retained theability to mobilize calcium. However collectively these residuescomprise an important submotif inasmuch as their deletion eliminatescytolytic activity. Conversion of Tyr 62 to either Phe or Ser eliminatedboth the cytotoxic and calcium responses. At the amino terminus of the18 residue segment, replacement of Tyr 51 with Phe abolished bothcalcium mobilization and cytolytic activity, while substitution of Leuwith Ser at position 50 eliminated the calcium response while onlypartially impairing cytolysis. Without being bound to a particularhypothesis, it is suspected that the inability of the Leu50Ser mutant tomobilize calcium in short term flow cytometric assays does not fullyreflect its ability to mediate a substantial increase in freeintracellular calcium ion over the longer time span of the cytolysisassay. However, calcium-insensitive cytolytic activity has been reportedfor some cytolytic T cell lines, and the possibility that a similarphenomenon underlies the results described herein has not been ruledout. Replacement of Asn48 with Ser partially impaired cytotoxicity insome experiments while having little effect in others.

To investigate the potential role of redundant sequence elements, theintracellular domain of ζ was divided into three segments, spanningresidues 33 to 65, 71 to 104, and 104 to 138. Each of these segments wasattached to a CD16:CD7 chimera by means of a MluI site introduced justdistal to the basic membrane anchoring sequences of the intracellulardomain of CD7 (see below; FIG. 11A). Comparison of the cytolyticefficacy of the three elements showed they were essentially equipotent(FIG. 11B). Sequence comparison (FIG. 11A) shows that the second motifbears eleven residues between tyrosines, whereas the first and thirdmotifs bear ten.

Although a precise accounting of the process of T cell activation hasnot been made, it is clear that aggregation of the antigen receptor, orof receptor chimeras which bear ζ intracellular sequences, triggerscalcium mobilization, cytokine and granule release, and the appearanceof cell surface markers of activation. The active site of ζ, a shortlinear peptide sequence probably too small to have inherent enzymaticactivity, likely interacts with one or at most a few proteins to mediatecellular activation. It is also clear that mobilization of free calciumis not by itself sufficient for cellular activation, as the ability tomediate cytolysis can be mutationally separated from the ability tomediate calcium accumulation.

As shown herein, addition of 18 residues from the intracellular domainof ζ to the transmembrane and intracellular domain of two unrelatedproteins allows the resulting chimeras to redirect cytolytic activityagainst target cells which bind to the extracellular portion of thefusion proteins. Although chimeras bearing the 18 residue motif areapproximately eight-fold less active than chimeras based on full lengthζ, the reduced activity can be attributed to the loss of transmembraneinteractions which normally allow wild-type ζ to form disulfide linkeddimers. That is, ζ deletion constructs which have the same carboxylterminus as the motif and lack transmembrane Cys and Asp residuestypically show slightly less activity than chimeras bearing only the 18residue motif.

The cytolytic competency element on which we have focused has twotyrosines and no serines or threonines, restricting the possiblecontributions of phosphorylation to activity. Mutation of eithertyrosine destroys activity, however, and although preliminaryexperiments do not point to a substantial tyrosine phosphorylationfollowing crosslinking of chimeric surface antigens bearing the 18reside motif, the possible participation of such phosphorylation at alow level cannot be excluded. In addition to the effects noted at thetwo tyrosine residues, a number of amino acid replacements at the aminoand carboxyl terminus of the motif weaken activity under conditions oflow receptor density.

Sequences similar to the ζ active motif can be found in the cytoplasmicdomains of several other transmembrane proteins, including the CD3δ andγ molecules, the surface IgM associated proteins mb1 and B29, and the βand γ chains of the high affinity IgE receptor, FcεRI (Reth, Nature338:383, 1989). Although the function of these sequences is uncertain,if efficiently expressed, each may be capable of autonomous T cellactivation, and such activity may explain the residual TCRresponsiveness seen in a zeta-negative mutant cell line (Sussman et al.,Cell 52:85, 1988).

ζ itself bears three such sequences, approximately equally spaced, and arough trisection of the intracellular domain shows that each is capableof initiating a cytolytic response. η, a splice isoform of ζ (Jin etal., supra, 1990; Clayton et al., Proc. Natl. Acad. Sci. USA 88:5202,1991), lacks the carboxyl half of the third motif. Because removal ofthe carboxyl half of the first motif abolishes activity, it appearslikely that the majority of the biological effectiveness of η can beattributed to the first two motifs. Although by different measures η isequally as active as ζ in promoting antigen-mediated cytokine release(Bauer et al., Proc. Natl. Acad. Sci. USA 88:3842, 1991) or redirectedcytolysis (see above), η is not phosphorylated in response to receptorstimulation (Bauer et al., supra, 1991). Thus either the presence of allthree motifs is required for phosphorylation, or the third motifrepresents a favored substrate for an unidentified tyrosine kinase.

EXAMPLE IX Cytolytic Signal Transduction by Human Fc Receptor

To evaluate the actions of different human Fc receptor subtypes,chimeric molecules were created in which the extracellular domain of thehuman CD4, CD5 or CD16 antigens were joined to the transmembrane andintracellular domains of the FcRIIγA, B1, B2, and C subtypes(nomenclature of Ravetch and Kinet, Ann. Rev. Immunol. 9:457, 1991).Specifically, cDNA sequences corresponding to the transmembrane andcytoplasmic domains of the previously described FcRIIA, B1, and B2isoforms were amplified from the preexisting clone PC23 or from a humantonsil CDNA library (constructed by standard techniques) using thefollowing synthetic oligonucleotides primers:

CCC GGA TCC CAG CAT GGG CAG CTC TT (SEQ ID NO: 18; FcRII A forward);

CGC GGG GCG GCC GCT TTA GTT ATT ACT GTT GAC ATG GTC GTT (SEQ ID NO: 19;FcRII A reverse);

GCG GGG GGA TCC CAC TGT CCA AGC TCC CAG CTC TTC ACC G (SEQ ID NO: 20;FcRII B1 and FcRII B2 forward); and

GCG GGG GCG GCC GCC TAA ATA CGG TTC TGG TC (SEQ ID NO: 21; FcRII B1 andFcRII B2 reverse).

These primers contained cleavage sites for the enzymes BamHI and NotI,respectively, indented 6 residues from the 5′ end. The NotI site wasimmediately followed by an antisense stop codon, either CTA or TTA. Allprimers contained 18 or more residues complementary to the 5′ and 3′ends of the desired fragments. The cDNA fragment corresponding to theFcRIIγC cytoplasmic domain, which differs from the IIA isoform in onlyone amino acid residue (L for P at residue 268) was generated by sitedirected mutagenesis by overlap PCR using primers of sequence:

TCA GAA AGA GAC AAC CTG AAG AAA CCA ACA A (SEQ ID NO:22) and

TTG TTG GTT TCT TCA GGT TGT GTC TTT CTG A (SEQ ID NO: 23).

The PCR fragments were inserted into vaccinia virus expression vectorswhich contained the CD16 or CD4 extracellular domains respectively andsubsequently inserted into wild type vaccinia by recombination at thethymidine kinase locus, using selection for cointegration of E coli gptto facilitate identification of the desired recombinants. The identitiesof all isoforms (shown in FIG. 12) were confirmed by dideoxy sequencing.

Production of the chimeric receptor proteins was further confirmed byimmunoprecipitation studies. Approximately 10⁷ JRT3.T3.5 cells wereinfected for one hour in serum free IMDM medium with recombinantvaccinia at a multiplicity of infection of at least ten. Twelve hourspost-infection, the cells were harvested and surface labeled with 0.5mCi ¹²⁵I per 10⁷ cells using the lactoperoxidase/glucose oxidase method(Clark and Einfeld, supra). The labeled cells were collected bycentrifugation and lysed 1% NP-40, 0.1 mM MgCl₂, 5 mM KCl, 0.2Miodoacetamide and 1 mM PMSF. Nuclei were removed by centrifugation, andCD16 fusion proteins immunoprecipitated with antibody 4G8 and anti-mouseIgG agarose. Samples were electrophoresed under reducing conditions. Allimmunoprecipitated chimeric receptor molecules were of the expectedmolecular masses.

To test the ability of the chimeric receptors to mediate an increase incytoplasmic free calcium ion, the recombinant viruses were used toinfect the TCR⁻ mutant Jurkat cell line JRT3.T3.5 (as described herein)and cytoplasmic free calcium was measured in the cells (as describedherein) following crosslinking of the receptor extracellular domainswith monoclonal antibody 3G8 or Leu-3A (as described herein). Theseexperiments revealed that the intracellular domains of FcRγII A and Cwere capable of mediating an increase in cytoplasmic free calcium ionafter crosslinking of the extracellular domains, whereas theintracellular domains of FcRγII B1 and B2 were inactive under comparableconditions (FIGS. 13A and 13B). The CD4, CD5 and CD16 hybrids of FcRγIIA shared essentially equal capacity to promote the calcium response(FIGS. 13A-B). Other cell lines, from both monocytic and lymphocyticlineages, were capable of responding to the signal initiated bycrosslinking of the extracellular domains.

To explore the involvement of the different FcRγII intracellular domainsin cytolysis, human cytotoxic T lymphocytes (CTL) were infected withvaccinia recombinants expressing CD16:FcRγII A, B1, B2 and C chimeras.The infected cells were then cocultured with ⁵¹Cr-loaded hybridoma cells(i.e., 3G8 10−2 cells) which expressed cell surface antibody to CD16. Inthis assay CTLs bearing the CD16 chimera killed the hybridoma targetcells (allowing release of free ⁵¹Cr) if the CD16 extracellular domainof the chimera has been joined to an intracellular segment capable ofactivating the lymphocyte effector program; this cytolysis assay isdescribed in detail below. FIG. 14A shows that CTL armed withCD16:FcRγIIA and C, but not FcRγII B1 or B2, are capable of lysingtarget cells expressing cell surface anti-CD16 antibody.

To eliminate the possibility that the specific cytolysis was in some wayattributable to interaction with the CD16 moiety, cytolysis experimentswere conducted in which the FcRII intracellular domains were attached toa CD4 extracellular domain. In this case the target cells were HeLacells expressing HIV envelope gp120/41 proteins (specifically, HeLacells infected with the vaccinia vector vPE16 (available from theNational Institute of Allergy and Infections Disease AIDS Depository,Bethesda, Md.). As in the CD16 system, target cells expressing HIVenvelope were susceptible to lysis by T cells expressing the CD4:FcRγIIA chimera, but not FcRγII B1 or B2 (FIG. 14B).

The intracellular domains of FcRγII A and C share no appreciablesequence homology with any other protein, including the members of theextended FcRγ/TCRζ family. To define the sequence elements responsiblefor induction of cytolysis, 5′ and 3′ deletions of the intracellulardomain coding sequences (described below and shown in FIG. 15A) wereprepared and were evaluated for efficacy in calcium mobilization andcytolysis assays (as described herein). In the experiments in which theamino terminal portion of the intracellular domain was removed, thetransmembrane domain of FcRγII was replaced with the transmembranedomain of the unrelated CD7 antigen to eliminate the possiblecontribution of interactions mediated by the membrane-spanning domain.

FIGS. 15B and 15C show that removal of the 14 carboxyl-terminalresidues, including tyrosine 298, resulted in a complete loss ofcytolytic capacity and a substantial reduction in calcium mobilizationpotential. Further deletion to just before tyrosine 282 gave anidentical phenotype (FIGS. 15B and 15C). Deletion from the N-terminus ofthe intracellular domain to residue 268 had no substantial effect oneither calcium profile or cytolytic potency, whereas deletion to residue275 markedly impaired free calcium release but had little effect oncytolysis (FIGS. 15D and 15E). Further deletion, to residue 282, gaveFcRγII tails which lacked the ability to either mobilize calcium ortrigger cytolysis (FIGS. 15D and 15E). The ‘active element’ defined bythese crude measures is relatively large (36 amino acids) and containstwo tyrosines separated by 16 residues.

EXAMPLE X Targeted Cytolysis by Lymphocytes Bearing Chimeric CD4Receptors Which Do Not Support Infection

As discussed above, effector molecules may be engineered which redirectthe cytolytic activity of CTLs in an MHC-independent manner. Forexample, a chimera composed of the extracellular domain of CD4 fused tothe ζ chain in a human CTL clone, WH3, specifically kills target cellsdisplaying the surface envelope glycoprotein of HIV-1, gp120. Since theextracellular domain of the CD4 molecule confers susceptibility to HIVinfection, however, the armed CTLs may become targets for the virus,resulting in a decrease in their potency (Dalgleish et al., Nature312:767 (1984); Klatzmann et al., Nature 312:767 (1984)). To preventsuch an outcome, chimeric effector molecules were designed based on CD4which are effective in specifically targeting HIV-infected cells forcell-mediated killing but which do not confer susceptibility toinfection by HIV.

A tripartite fusion protein was created by genetic apposition of theextracellular domain of CD4 (FIG. 23) to the hinge, second, and thirdconstant domains of human IgG1 heavy chain (Zettlmeissl et al., DNA CellBiol. 9:347 (1990)) (FIG. 25), which were joined in this case to aportion of the first transmembrane exon of human membrane-bound IgG1,followed by a portion of the human CD7 antigen consisting of thesequences between the sole Ig-like domain and the stop transfer sequencefollowing the transmembrane domain (Aruffo and Seed, EMBO J. 6:3313(1987)) (FIG. 26). The primary amino acid sequence of the extracellularmoiety of the CD7 segment consisted of a proline-rich region suggestiveof a stalk-like structure which projects the Ig-like domain away fromthe cell surface (Aruffo and Seed, EMBO J. 6:3313 (1987)) (FIG. 26).Recombinant vaccinia viruses were prepared to express this and relatedchimeras as described herein. In particular, recombinant vacciniaviruses were generated by homologous recombination in CV-1 cells. Atleast two rounds of plaque visualization with OKT4 or Leu3a followed byplaque purification was performed for each stock prior to preparation ofhigh titer stocks in CV-1 cells.

The tripartite chimera (CD4(D1-D4):Ig:CD7) (FIG. 20, molecule “A”)showed efficient cell surface expression and was tested for the abilityto act as an HIV receptor in a vaccinia-based syncytia formation assay(Lifson et al., Nature 323:725 (1986)); Ashorn et al., J. Virol. 64:2149(1990)). HeLa cells infected with a recombinant vaccinia virus (vPE16)encoding the envelope glycoprotein of HIV-1 (Earl et al., J. Virol.64:2448 (1990)) were co-cultured with HeLa cells infected either withCD4, CD4:ζ, or CD4(D1-D4):Ig:CD7. Six cm dishes of HeLa cells (ATCC,Rockville, Md.) at 50% confluence were infected in serum-free medium for1 hour at an approximate multiplicity of infection (MOI) of 10. Thecells were incubated for an additional 5-6 hours in complete medium andthen detached with phosphate buffered saline (PBS) containing 1 mM EDTA.Cells expressing envelope and CD4 chimera were mixed at a 1:1 ratio, andreplated in 6 cm dishes with complete medium. Syncytia were scored at6-8 hours post-cocultivation and photographed.

Co-cultures of CD4 and vPE16 led to formation of readily detectablemultinucleated giant cells. Also, a chimera consisting of theextracellular domain of CD4 fused to the ζ chain of the TCR (FIG. 27)(CD4:ζ) was able to mediate syncytia formation, whereas cells expressingCD4(D1-D4):Ig:CD7 gave no sign of cell fusion. We also tested aconstruct expressing only the first and second domains of CD4 (FIG. 24),CD4(D1,D2):Ig:CD7 (FIG. 20, molecule “B”), since in another context theamino terminal two domains of the CD4 have been shown to be necessaryfor infectivity by HIV (Landau et al., Nature 334:159 (1988)). Thismolecule proved insusceptible to HIV-induced syncytia formation as well.Binding studies with soluble ¹²⁵I-labelled gp120 established that bothCD4(D1-D4):Ig:CD7 and CD4(D1,D2):Ig:CD7 had uncompromised affinity forgp120.

We next determined whether chimeric molecules which resisted syncytiumformation would be able to redirect cell killing if endowed with atrigger moiety as described herein. We fused the intracellular domain ofζ (FIG. 27) to the 3′ end of CD4(D1-D4):Ig:CD7 and CD4(D1,D2):Ig:CD7 andprepared the corresponding recombinant vaccinia viruses. Theseconstructs, CD4(D1-D4):Ig:CD7:ζ and CD4(D1,D2):Ig:CD7:ζ (FIG. 20,molecules “C” and “D”), were expressed in the human CTL clone WH3 andtested for their ability to target and kill HeLa cells expressing thesurface envelope glycoprotein of HIV (using the methods describedherein). FIG. 21 shows that the intracellular domain of ζ fused toeither CD4(D1-D4):Ig:CD7 or CD4(D1,D2):Ig:CD7 can confer killingability; constructs lacking the ζ chain were not able to mediate thisactivity. CD4:ζ, a positive control, mediated a slightly more effectivecytotoxicity, and CD4(D1,D2):Ig:CD7:ζ a somewhat less effectivecytotoxicity than CD4(D1-D4):Ig:CD7:ζ (FIG. 21). However, it is clearthat both CD4(D1-D4):Ig:CD7:ζ and CD4(D1,D2):Ig:CD7:ζ chimeras have thecapacity to mediate specific killing of cells expressing HIV envelopeproteins on their surface. The tetrapartite chimeras were consistentlyincapable of mediating syncytium formation in the vaccinia-based assay.We have also demonstrated that a single ζ motif of the sort shown inFIG. 11A is sufficient to confer cytolytic activity to a CD4(D1-D4)chimera.

Radioimmunoprecipitation experiments established that the fusionmolecules were predominantly if not entirely dimers. In theseexperiments, protein-A agarose beads were used to immunoprecipitate thesolubilized extract of metabolically labelled HeLa cells infected withrecombinant vaccinia expressing CD4(D1-D4):Ig:CD7:ζ andCD4(D1,D2):Ig:CD7:ζ chimeras. The immunoprecipitated material wasfractionated by polyacrylamide gel electrophoresis under reducing andnonreducing conditions. In particular, approximately 5×10⁶ HeLa-S3 cellswere infected as described above for vPE16 with the appropriate vacciniavirus stock. Cells were metabolically labelled with 200 μCi/ml ofTran³⁵S-Label (ICN Radiochemicals, Irvine, Calif.) for 6-8 hours incysteine and methionine-deficient medium and detached with PBScontaining 1 mM EDTA. Cells were subsequently pelleted and lysed in 150mM NaCl, 50 mM Tris pH 7.5, 5 mM EDTA, 0.5% NP-40, 0.1% SDS, 5 mM EDTA,lmM PMSF. Following the removal of the nuclei by centrifugation, onefifth of each cell extract was adsorbed onto washed protein A-conjugatedagarose beads for 2 hours at 4° C. The beads were subsequently washedwith PBS containing 1% NP-40 and eluted in sample buffer containing SDSin the presence or absence of mercaptoethanol. The results of theseexperiments demonstrated that the majority of the immunoprecipitatedCD4(D1-D4):Ig:CD7:ζ and CD4(D1,D2):Ig:CD7:ζ chimeras migrated as dimersof the expected molecular mass under nonreducing conditions.

To directly evaluate the ability of cells expressing the CD4 fusionmolecules to support HIV infection, we performed long term infectivitystudies on transfectants expressing CD4(D1-D4):Ig:CD7 andCD4(D1,D2):Ig:CD7. Stable transfectants of CD4(D1-D4):Ig:CD7 andCD4(D1,D2):Ig:CD7 and CD4 were prepared in a subline of 293 cells, areadily transfectable cell line of human embryonic kidney origin. Thechimeric molecules were subcloned in bidirectional vectors in which thehygromycin B gene was driven by the herpes simplex virus thymidinekinase promoter. A 60-70% confluent 10 cm dish of cells was transfectedwith 10 μg of this plasmid DNA by calcium phosphate coprecipitation.Prior to transfection, the plasmids were linearized at the unique Sfi Isite, and the ends made flush with T4 DNA polymerase. At 24 hourspost-transfection, the cells were split fourfold and at 48 hourspost-transfection the cells were put under selection with hygromycin B(Sigma, St. Louis, Mo.) at 400 μg/ml. Every 3-4 days, cells weresupplied with fresh medium containing hygromycin.

Resistant colonies were picked, expanded, and their expression assessedby indirect immunofluorescence using fluorescein-conjugated anti-humanIgG Fc (Organon Teknika, West Chester, Pa.) or Q4120, an antibodyreactive with human CD4 (Sigma) followed by flow cytometry (Coulter,Hialeah, Fla.). Two independent clones from each construct with levelsof cell surface CD4 comparable to that shown by the other cell lineswere selected for analysis. FIG. 22 shows that, following exposure toHIV, p24 was detected in the CD4 stable transfectant cultures as earlyas 3 days post-infection. The presence of multinucleated giant cells andcharacteristic ballooning was evident as early as 5 days post-infectionin these cultures. No significant p24 levels or evidence ofmultinucleated giant cells was detectable in the untransfected parentalcell line or in either of two independently derived isolates ofCD4(D1-D4):Ig:CD7 and CD4(D1,D2):Ig:CD7 transfectants after 32 days inculture (FIG. 22).

Upon completion of the infectivity studies, cells were analyzed for cellsurface CD4 expression. CD4 surface epitope density was significantlyreduced in infected cultures expressing CD4, consistent with viraldown-modulation, but was unaffected in cultures expressingCD4(D1-D4):Ig:CD7 and CD4(D1,D2):Ig:CD7. These experiments establishthat it is possible to create chimeric molecules bearing the apical twodomains of CD4 which, when fused to T cell receptor ζ chain, have thecapacity to target and kill HIV-infected cells, but which do not supportCD4-mediated HIV infection.

Additional experiments suggest that it is the physical distance betweenthe extracellular domain of the CD4 molecule and the lipid bilayer thatconfers the ability to resist HIV infection. In a first experiment, weconstructed a chimeric molecule bearing a deletion of the CD7 stalk andtransmembrane domain; this deletion removed the proline rich region ofthe CD7 transmembrane portion. When this domain was fused to theextracellular domain of CD4, it maintained its ability to efficientlyanchor the extracellular domain of the CD4 molecule, as measured by cellsurface expression of the CD4 molecule (as described herein). However,the potential to resist syncytium formation induced by the HIV envelopeglycoprotein was lost. Thus, deletion of the proline-rich region of theCD7 molecule, a region likely to form an α-helical coil structure,effectively reduced the distance between the extracellular domain of CD4and the lipid bilayer and abrogated the ability of the chimera to resistsyncytium formation.

In a second experiment, we demonstrated that the ability to resistHIV-induced syncytium formation may be conferred upon a CD4/CD5 chimerawhich had previously been documented to serve as a transmembrane anchorfor a CD4 extracellular domain but which was unable to resistHIV-induced syncytium formation. In this experiment, the hinge, CH2, andCH3 domains of the human IgG1 heavy chain were inserted into the CD4/CD5molecule; the resulting chimera resisted syncytium formation, againsuggesting that the distance afforded by the immunoglobulin domains issufficient to confer resistance to HIV-induced syncytium formation.

In a third experiment, a CD4 domain was extended varying distances fromthe cell membrane using synthetic alpha helices of varying length. Inparticular, synthetic oligonucleotides representing repeated alphahelical motifs of lysine and glutamic acid residues flanked by twoalanine residues were designed (see FIG. 28 for the primary nucleic acidand amino acid sequences). In previous studies, such amino acidsequences were found to occur with high frequency in alpha helices,suggesting that such repeated motifs would adopt an alpha helicalconformation and that placement of such alpha helices between thetransmembrane domain and extracellular domains of CD4 would project CD4away from the cell membrane. By varying the length of the alpha helicalsegment, a calculation of the projection distance necessary to resistHIV entry was determined based on known values for alpha helical riseand turn. These results are presented in Table 1.

TABLE 1 Syncytia Thy-1 Formation Expression A. CD4 + H + CH2 + CH3 +CD7tm + stk − − B. CD4 (D1,D2) + H + CH2 + CH3 + − − CD7tm + stk C.CD4 + CD7tm + stk +/−^((a)) + D. CD4 + CD7tm (long version) + + E. CD4 +CD7tm (short version) + + F. CD4 + CD5tm + + G. CD4 + CH2 + CH3 + CD5tm− − H. CD4 + CH3 + CD5tm − ND I. CD4 + CD34tm + + J. CD4 + syntheticalpha helix ND + (24 angstroms) + CD34tm K. CD4 + synthetic alpha helixND +/−^((a)) (48 angstroms) + CD34tm L. CD4 + synthetic alpha helix ND −(72 angstroms) + CD34tm ^(a)Substantial reduction in the number ofsyncytia or thy-1-expressing cells.

In this Table, “CD4” represents CD4(D1-D4) unless otherwise noted; “H”,“CH2”, and “CH3” represent the hinge, CH2, and CH3 regions of the humanIgG1 heavy chain, respectively; “CD7tm and stk” represents the CD7transmembrane and stalk regions; “CD7tm (long version)” and “CD7tm(short version)” represent respectively the CD7 transmembrane region andthe CD7 transmembrane region deleted for the proline-rich domain (asdiscussed above); “CD5tm” represents the CD5 transmembrane region; and“CD34tm” represents the CD34 transmembrane region. In entries J-L, thelength of the alpha helical region is denoted in angstroms; these valuesare based on the fact that there are 3.6 residues per turn of an alphahelix, corresponding to 5.4 A (or 1.5A per residue). Accordingly, a 16residue alpha helix would project the extracellular domain of CD4 about24 angstroms. The 48 and 72 angstrom alpha helices were constructed bysequential concatemerization of the BstY1 fragment into the fragment'sunique BamH1 site (see FIG. 28), followed by selection of clones withthe proper orientation.

Syncytia formation was scored in co-cultivation assays with HeLa cellsexpressing the HIV-1 envelope glycoprotein from the vaccinia virusvPE-16 construct (see above).

Thy-1 expression was measured as follows. A live retrovirus vector wasconstructed based on the hxb.2 clone of HIV-1. In this vector, thenon-essential nef gene was replaced with the coding sequence of ratthy-1, an efficiently expressed cell surface molecule that is anchoredto the membrane by a phosphatidyl-inositol linkage. The virus derivedfrom this molecular clone, designated hxb/thy-1, was infectious asevidenced by its cytopathological effects and by the production of p24in culture supernatants of infected C8166 cells (a human CD4⁺ leukemicT-cell line). In addition, upon exposure to hxb/thy-1, HeLa cellstransiently transfected with CD4 showed signs of thy-1 expression in asearly as 18 hours post-infection, as would be expected of a messageregulated in a nef-like manner. Messages encoded by the nef genenormally fall into a class of viral regulatory proteins which aremultiply spliced and lack the rev-response element. These messages canaccumulate constitutively in the cytoplasm as early viral gene products.The thy-1 messages were expected to be similarly regulated, that is, tooccur early in the life cycle of the virus. In short, this systemfacilitated the assay of HIV entry, with thy-1 expression employed as asurrogate for viral entry. Various CD4-based chimeras were transientlytransfected into HeLa cells using standard DEAE-dextran methods. Thetransfected cells were exposed to hxb/thy-1 virus at 48 hourspost-transfection and scored for thy-1 expression at 24-48 hourspost-infection. In the results shown in Table 1, thy-1 expression wasmeasured at 24 hours post-infection using a commercially available Thy-1monoclonal antibody (Accurate).

From the data presented in Table 1, we concluded that the extracellulardomains of CD4 should optimally be projected away from the cell membraneby at least 48 angstroms, and preferably by at least 72 angstroms inorder to resist HIV-1 infection.

Using a strategy similar to the general strategy described herein,chimeras based on anti-HIV envelope antibodies may be constructed whichtarget HIV-infected cells. Examples of such antibodies are described inGorny et al., Proc. Natl. Acad. Sci. USA 86:1624 (1989) and Marasco etal., J. Clin. Invest. 90:1467 (1992).

EXAMPLE XI Use of Projected CD4 Molecules as HIV Decoys

As demonstrated herein, cells bearing CD4 domains projected away fromthe cell surface resist HIV infectivity. Accordingly, such CD4-bearingcells are useful as decoys to bind circulating HIV and reduce viraltiters in HIV-infected individuals. Preferably, the CD4 domain ispresented on a cell that naturally passes through the lymph nodes;useful host cells include any cell that plays a role in immune cellclearance as well as any other cell naturally present in the lymph nodefollicles. Particular examples include, without limitation, macrophages,T cells (e.g., helper T cells), B cells, neutrophils, dendritic cells,and follicular dendritic cells.

Any CD4 domain capable of binding HIV, including the D1-D4 and D1,D2domains described herein, may be utilized in this method of theinvention. For at least some embodiments (for example, those describedabove), the intracellular and/or transmembrane domain portions of thechimera may be chosen from any protein or any amino acid sequence.

EXAMPLE XII Additional T Cell Receptor and B Cell Receptor TriggerProteins

Other intracellular and transmembrane signal transducing domainsaccording to the invention may be derived from the T cell receptorproteins, CD3 delta and T3 gamma, and the B cell receptor proteins, mb1and B29. The amino acid sequences of these proteins are shown in FIG. 16(CD3 delta; SEQ ID NO: 24), FIG. 17 (T3 gamma; SEQ ID NO: 25), FIG. 18(mb1; SEQ ID NO: 26), and FIG. 19 (B29; SEQ ID NO: 27). The portions ofthe sequences sufficient for cytolytic signal transduction (andtherefore preferably included in a chimeric receptor of the invention)are shown in brackets. Chimeric receptors which include these proteindomains are constructed and used in the therapeutic methods of theinvention generally as described above.

EXAMPLE XIII Experimental Methods Vaccinia Infection andRadioimmunoprecipitation

Approximately 5×10⁶ CV1 cells were infected for one hour in serum freeDME medium with recombinant vaccinia at a multiplicity of infection(moi) of at least ten (titer measured on CV1 cells). The cells wereplaced in fresh medium after infection and labelled metabolically with200 μCi/ml ³⁵S-methionine plus cysteine (Tran³⁵S-label, ICN; Costo Mesa,Calif.) in methionine and cysteine free DMEM (Gibco; Grand Island, N.Y.)for six hours. The labelled cells were detached with PBS containing 1 mMEDTA, collected by centrifugation, and lysed in 1% NP-40, 0.1% SDS, 0.15M NaCl, 0.05M Tris pH 8.0, 5 mM EDTA, and 1 M PMSF. Nuclei were removedby centrifugation, and CD4 proteins immunoprecipitated with OKT4antibody and anti-mouse IgG agarose (Cappel, Durham, N.C.). Samples wereelectrophoresed through 8% polyacrylamide/SDS gels under non-reducing(NR) and reducing (R) conditions. Gels containing ³⁵S-labelled sampleswere impregnated with En³Hance (New England Nuclear, Boston, Mass.)prior to autoradiography. Facilitated expression of the transmembraneform of CD16, CD16_(TM), was measured by comparing its expression in CV1cells singly infected with CD16_(TM) with expression in cells coinfectedwith viruses encoding CD16_(TM) and ζ or y chimeras. After infection andincubation for six hours or more, cells were detached from plates withPBS, 1 mM EDTA and the expression of CD16TM or the chimeras was measuredby indirect immunofluorescence and flow cytometry.

Calcium Flux Assay

Jurkat subline E6 (Weiss et al., J. Immunol. 133:123-128 (1984)) cellswere infected with recombinant vaccinia viruses for one hour in serumfree IMDM at an moi of 10 and incubated for three to nine hours in IMDM,10% FBS. Cells were collected by centrifugation and resuspended at 3×10⁶cells/ml in complete medium containing 1 mM Indo-1 acetomethoxyester(Grynkiewicz et al., J. Biol. Chem. 260:3340-3450 (1985)) (MolecularProbes) and incubated at 37° C. for 45 minutes. The Indo-1 loaded cellswere pelleted and resuspended at 1×10⁶/ml in serum free IMDM and storedat room temperature in the dark. Cells were analyzed for free calciumion by simultaneous measurement of the violet and blue fluorescenceemission by flow cytometry (Rabinovitch et al., J. Immunol. 137:952-961(1986)). To initiate calcium flux, either phycoerythrin (PE)-conjugatedLeu-3A (anti-CD4) (Becton Dickinson, Lincoln Park, N.J.) at 1 μg/ml wasadded to the cell suspension followed by 10 μg/ml of unconjugated goatanti-mouse IgG at time 0 or unconjugated 3G8 (anti-CD16) monoclonalantibody was added to the cell suspension at 1 μg/ml followed by 10μg/ml of PE-conjugated Fab₂′ goat anti-monse IgG at time 0. Histogramsof the violet/blue emission ratio were collected from the PE positive(infected) cell population, which typically represented 40-80% of allcells. The T cell antigen receptor response in uninfected cells wastriggered by antibody OKT3, without crosslinking. For experimentsinvolving CD16 chimeric receptors, samples showing baseline drift towardlower intracellular calcium (without antibody) were excluded from theanalysis. Histogram data were subsequently analyzed by conversion of thebinary data to ASCII using Write Hand Man (Cooper City, Fla.) software,followed by analysis with a collection of FORTRAN programs. Theviolet/blue emission ratio prior to the addition of the second antibodyreagents was used to establish the normalized initial ratio, set equalto unity, and the resting threshold ratio, set so that 10% of theresting population would exceed threshold.

Cytolysis Assay

Human T cell line WH3, a CD8⁺ CD4⁻ HLA B44 restricted cytolytic line wasmaintained in IMDM, 10% human serum with 100 U/ml of IL-2 and wasperiodically stimulated either nonspecifically with irradiated (3000rad) HLA-unmatched peripheral blood lymphocytes and 1 μg/ml ofphytohemagglutinin, or specifically, with irradiated B44-bearingmononuclear cells. After one day of nonspecific stimulation, the PHA wasdiluted to 0.5 μg/ml by addition of fresh medium, and after three daysthe medium was changed. Cells were grown for at least 10 days followingstimulation before use in cytotoxicity assays. The cells were infectedwith recombinant vaccinia at a multiplicity of infection of at least 10for one hour in serum free medium, followed by incubation in completemedium for three hours. Cells were harvested by centrifugation andresuspended at a density of 1×10⁷ cells/ml. 100 μl were added to eachwell of a U-bottom microtiter plate containing 100 μl/well of completemedium. Cells were diluted in two-fold serial steps. Two wells for eachsample did not contain lymphocytes, to allow spontaneous chromiumrelease and total chromium uptake to be measured. The target cells, fromHeLa subline S3, were infected in 6.0 or 10.0 cm plates at anapproximate moi of 10 for one hour in serum free medium, followed byincubation in complete medium for three hours. They were then detachedfrom the dishes with PBS, 1 mM EDTA and counted. An aliquot of 10⁶target cells (HeLa, Raji, or RJ2.2.5 cells for the CD4 chimeric receptorexperiments and 3G8 10−2 cells; Shen et al., Mol. Immunol. 26:959 (1989)for the CD16 chimeric receptor experiments) was centrifuged andresuspended in 50 μl of sterile ⁵¹Cr-sodium chromate (1 mCi/ml, DupontWilmington, Del.) for one hour at 37° C. with intermittent mixing, thenwashed three times with PBS. 100 μl of labelled cells resuspended inmedium at 10⁵ cells/ml were added to each well. Raji and RJ2.2.5 targetcells were labelled in the same manner as HeLa cells. The microtiterplate was spun at 750×g for 1 minute and incubated for 4 hours at 37° C.At the end of the incubation period, the cells in each well wereresuspended by gentle pipetting, a sample removed to determine the totalcounts incorporated, and the microtiter plate spun at 750×g for 1minute. 100 μl aliquots of supernatant were removed and counted in agamma ray scintillation counter. The percent killing was corrected forthe fraction of infected target cells (usually 50-90%) measured by flowcytometry. For infected effector cells the effector:target ratio wascorrected for the percent of cells infected (usually 20-50% for the CD4chimeric receptor experiments and >70% for the CD16 chimeric receptorexperiments).

In Vitro Mutagenesis of the ζ Sequence

To create point mutations in amino acid residues 11 and or 15 of the ζsequence, synthetic oligonucleotide primers extending from the BamHIsite upstream of the ζ transmembrane domain, and converting native ζresidue 11 from Cys to Gly (C11G) or residue 15 from Asp to Gly (D15G)or both (C11G/D15G) were prepared and used in PCR reactions to generatemutated fragments which were reinserted into the wild type CD4:ζconstructs.

To create ζ deletions, ζ cDNA sequences were amplified by PCR usingsynthetic oligonucleotide primers designed to create a stop codon (UAG)after residues 50, 59, or 65. The primers contained the cleavage sitefor the enzyme NotI indented five or six residues from the 5′ end,usually in a sequence of the form CGC GGG CGG CCG CTA (SEQ ID NO: 11),where the last three residues correspond to the stop anticodon. The NotIand stop anticodon sequences were followed by 18 or more residuescomplementary to the desired 3′ end of the fragment. The resultingchimeras were designated CD16:ζ Y51*, CD16:ζ E60* and CD16:ζ D66*respectively. The BamHI site upstream of the transmembrane domain andthe NotI site were used to generate fragments that were reintroducedinto the wild type CD16:ζ construct. Monomeric ζ chimeras were createdby liberating the ζ transmembrane and membrane proximal intracellularsequences by BamHI and SacI digestion of the Asp⁻ and Cys⁻ CD4:ζconstruct described above and inserting the fragment into the CD16:ζE60* and CD16:ζ D66* construct respectively.

CD16:7:ζ (48-65) and CD16:7ζ (48-59) Tripartite Chimera Construction

To prepare the construct CD16:ζ D66*, the ζ cDNA sequence correspondingto the transmembrane domain and the 17 following residues of thecytoplasmic domain was replaced by corresponding transmembrane andcytoplasmic domain obtained from the CD5 and CD7 cDNA. The CD5 and CD7fragments were generated by a PCR reaction using forwardoligonucleotides including a BamHI restriction cleavage site andcorresponding to the region just upstream of the transmembrane domain ofCD5 and CD7 respectively and the following reverse oligonucleotidesoverlapping the CD5 and CD7 sequences respectively and the ζ sequencewhich contained the SacI restriction cleavage site.

CD5:ζ: CGC GGG CTC GTT ATA GAG CTG GTT CTG GCG CTG CTT CTT CTG (SEQ IDNO: 12)

CD7:ζ: CGC GGG GAG CTC GTT ATA GAG CTG GTT TGC CGC CGA ATT CTT ATC CCG(SEQ ID NO: 13).

The CD5 and CD7 PCR products were digested with BamHI and SacI andligated to BamHI and SacI digested CD16:ζ E60* and replacing the ζsequence from BamHI to SacI by the CD7 fragment. To make the constructsCD16:CD5 and CD16:CD7, CD5 and CD7 fragments were obtained by PCR usingan oligonucleotide containing a NotI restriction cleavage site andencoding a stop codon (UAA) after the residue Gln4l6 and Ala193 of CD5and CD7 respectively. The CD5 and CD7 PCR fragment were digested withBamHI and NotI and inserted in the CD16:ζ Asp66* construct.

In Vitro Mutagenesis of the N-terminal Residues within the ζ CytolyticSignal-Transducing Motif

Synthetic oligonucleotide primers extending from the SacI site insidethe ζ motif and converting native residue 48 from Asn to Ser (N48S),residue 50 from Leu to Ser (L50S) and residue 51 from Tyr to Phe (Y51F)were synthesized and used in a PCR reaction to generate fragments thatwere reintroduced into the wild type CD16:7:ζ (48-65) construct.

In Vitro Mutagenesis of C-terminal Residues within the ζ CytolyticSignal-Transducing Motif

Synthetic oligonucleotide primers extending from the NotI site 3′ to thestop codon and converting native residue 60 from Glu to Gln (E60Q),residue 61 from Glu to Gln (E61Q), residue 62 from Tyr to Phe or Ser(Y62F or Y62S) and residue 63 from Asp to Asn (D63N) were synthesizedand used in PCR to generate fragments that were subcloned into the wildtype CD16:ζ D66* construct from the BamHI site to the NotI site.

CD16:7:ζ (33-65), CD16:7:ζ (71-104), CD16:7:ζ (104-137) ChimeraConstructions

A CD7 transmembrane fragment bearing MluI and NotI sites at the junctionbetween the transmembrane and intracellular domains was obtained by PCRusing an oligonucleotide with the following sequence: CGC GGG GCG GCCACG CGT CCT CGC CAG CAC ACA (SEQ ID NO:14). The resulting PCR fragmentwas digested with BamHI and NotI and reinserted into the CD16:7:ζ(48-65) construct. ζ fragments encoding residues 33 to 65, 71 to 104,and 104 to 137 were obtained by PCR reaction using pairs of primerscontaining MluI sites at the 5′ end of the forward primers and stopcodons followed by NotI sites at the 5′ end of the reverse primers. Ineach case the restriction sites were indented six residues from the 5′terminus of the primer to insure restriction enzyme cleavage.

ζ 33: CGC GGG ACG CGT TTC AGC CGT CCT CGC CAG CAC ACA (SEQ ID NO: 15);

ζ 71: CGC GGG ACG CGT GAC CCT GAG ATG GGG GGA AAG (SEQ ID NO: 16); and

ζ 104: CGC GGG ACG CGT ATT GGG ATG AAA GGC GAG CGC (SEQ ID NO: 17).

Construction of FcRγIIA Deletion Mutants

Carboxyl terminal FcRIIA deletion mutants were constructed by PCR in thesame fashion as for the full length constructs, converting the sequencesencoding tyrosine at positions 282 and 298 into stop codons (TAA). TheN-terminal deletions were generated by amplifying fragments encodingsuccessively less of the intracellular domain by PCR, usingoligonucleotides which allowed the resulting fragments to be insertedbetween MluI and NotI restriction sites into a previously constructedexpression plasmid encoding the CD16 extracellular domain fused to theCD7 transmembrane domain, the latter terminating in a MluI site and thejunction between the transmembrane and the intracellular domain.

OTHER EMBODIMENTS

The examples described above demonstrate that aggregation of ζ, η, or γchimeras suffices to initiate the cytolytic effector cell response in Tcells. The known range of expression of ζ, η, and γ, which includes Tlymphocytes, natural killer cells, basophilic granulocytes, macrophages,and mast cells, suggests that conserved sequence motifs may interactwith a sensory apparatus common to cells of hematopoietic origin andthat an important component of host defense in the immune system may bemediated by receptor aggregation events.

The potency of the cytolytic response and the absence of a response totarget cells bearing MHC class II receptors demonstrates that chimerasbased on ζ, η, or γ form the basis for a genetic intervention for AIDSthrough adoptive immunotherapy. The broad distribution of endogenous ζand γ and evidence that Fc receptors associated with γ mediatecytotoxicity in different cells types (Fanger et al., Immunol. Today10:92-99 (1989)) allows a variety of cells to be considered for thispurpose. For example, neutrophilic granulocytes, which have a very shortlifespan (≈4 h) in circulation and are intensely cytolytic, areattractive target cells for expression of the chimeras. Infection ofneutrophils with HIV is not likely to result in virus release, and theabundance of these cells (the most prevalent of the leukocytes) shouldfacilitate host defense. Another attractive possibility for host cellsare mature T cells, a population presently accessible to retroviralengineering (Rosenberg, Sci. Am. 262:62-69 (1990)). With the aid ofrecombinant IL-2, T cell populations can be expanded in culture withrelative ease, and the expanded populations typically have a limitedlifespan when reinfused (Rosenberg et al., N. Engl. J. Med. 323:570-578(1990)).

Under the appropriate conditions, HIV recognition by cells expressingCD4 chimeras should also provide mitogenic stimuli, allowing thepossibility that the armed cell population could respond dynamically tothe viral burden. Although we have focused here on the behavior of thefusion proteins in cytolytic T lymphocytes, expression of the chimerasin helper lymphocytes might provide an HIV-mobilized source of cytokineswhich could counteract the collapse of the helper cell subset in AIDS.Recent description of several schemes for engineering resistance toinfection at steps other than virus penetration (Friedman et al., Nature335:452-454 (1988); Green et al., Cell 58:215-223 (1989); Malim et al.,Cell 58:205-214 (1989); Trono et al., Cell 59:113-120 (1989); Buonocoreet al., Nature 345:625-628 (1990)) suggests that cells bearing CD4chimeras could be designed to thwart virus production by expression ofappropriate agents having an intracellular site of action.

The ability to transmit signals to T lymphocytes through autonomouschimeras also provides the ability for the regulation of retrovirallyengineered lymphocytes in vivo. Crosslinking stimuli, mediated forexample by specific IgM antibodies engineered to removecomplement-binding domains, may allow such lymphocytes to increase innumber in situ, while treatment with similar specific IgG antibodies(for example recognizing an amino acid variation engineered into thechimeric chain) could selectively deplete the engineered population.Additionally, anti-CD4 IgM antibodies do not require additionalcrosslinking to mobilize calcium in Jurkat cells expressing CD4:ζchimeras. The ability to regulate cell populations without recourse torepeated extracorporeal amplification may substantially extend the rangeand efficacy of current uses proposed for genetically engineered Tcells.

While the invention has been described in connection with specificembodiments thereof, it will be understood that it is capable of furthermodifications and this application is intended to cover variations,uses, or adaptations of the invention and including such departures fromthe present disclosure as come within the art to which the inventionpertains and as may be applied to the essential features hereinbeforeset forth as follows in the scope of the appended claims.

53 1728 base pairs nucleic acid double linear cDNA 1 ATGAACCGGGGAGTCCCTTT TAGGCACTTG CTTCTGGTGC TGCAACTGGC GCTCCTCCCA 60 GCAGCCACTCAGGGAAACAA AGTGGTGCTG GGCAAAAAAG GGGATACAGT GGAACTGACC 120 TGTACAGCTTCCCAGAAGAA GAGCATACAA TTCCACTGGA AAAACTCCAA CCAGATAAAG 180 ATTCTGGGAAATCAGGGCTC CTTCTTAACT AAAGGTCCAT CCAAGCTGAA TGATCGCGCT 240 GACTCAAGAAGAAGCCTTTG GGACCAAGGA AACTTCCCCC TGATCATCAA GAATCTTAAG 300 ATAGAAGACTCAGATACTTA CATCTGTGAA GTGGAGGACC AGAAGGAGGA GGTGCAATTG 360 CTAGTGTTCGGATTGACTGC CAACTCTGAC ACCCACCTGC TTCAGGGGCA GAGCCTGACC 420 CTGACCTTGGAGAGCCCCCC TGGTAGTAGC CCCTCAGTGC AATGTAGGAG TCCAAGGGGT 480 AAAAACATACAGGGGGGGAA GACCCTCTCC GTGTCTCAGC TGGAGCTCCA GGATAGTGGC 540 ACCTGGACATGCACTGTCTT GCAGAACCAG AAGAAGGTGG AGTTCAAAAT AGACATCGTG 600 GTGCTAGCTTTCCAGAAGGC CTCCAGCATA GTCTATAAGA AAGAGGGGGA ACAGGTGGAG 660 TTCTCCTTCCCACTCGCCTT TACAGTTGAA AAGCTGACGG GCAGTGGCGA GCTGTGGTGG 720 CAGGCGGAGAGGGCTTCCTC CTCCAAGTCT TGGATCACCT TTGACCTGAA GAACAAGGAA 780 GTGTCTGTAAAACGGGTTAC CCAGGACCCT AAGCTCCAGA TGGGCAAGAA GCTCCCGCTC 840 CACCTCACCCTGCCCCAGGC CTTGCCTCAG TATGCTGGCT CTGGAAACCT CACCCTGGCC 900 CTTGAAGCGAAAACAGGAAA GTTGCATCAG GAAGTGAACC TGGTGGTGAT GAGAGCCACT 960 CAGCTCCAGAAAAATTTGAC CTGTGAGGTG TGGGGACCCA CCTCCCCTAA GCTGATGCTG 1020 AGCTTGAAACTGGAGAACAA GGAGGCAAAG GTCTCGAAGC GGGAGAAGCC GGTGTGGGTG 1080 CTGAACCCTGAGGCGGGGAT GTGGCAGTGT CTGCTGAGTG ACTCGGGACA GGTCCTGCTG 1140 GAATCCAACATCAAGGTTCT GCCCACATGG TCCACCCCGG TGCACGCGGA TCCCAAACTC 1200 TGCTACTTGCTAGATGGAAT CCTCTTCATC TACGGAGTCA TCATCACAGC CCTGTACCTG 1260 AGAGCAAAATTCAGCAGGAG TGCAGAGACT GCTGCCAACC TGCAGGACCC CAACCAGCTC 1320 TACAATGAGCTCAATCTAGG GCGAAGAGAG GAATATGACG TCTTGGAGAA GAAGCGGGCT 1380 CGGGATCCAGAGATGGGAGG CAAACAGCAG AGGAGGAGGA ACCCCCAGGA AGGCGTATAC 1440 AATGCACTGCAGAAAGACAA GATGCCAGAA GCCTACAGTG AGATCGGCAC AAAAGGCGAG 1500 AGGCGGAGAGGCAAGGGGCA CGATGGCCTT TACCAGGACA GCCACTTCCA AGCAGTGCAG 1560 TTCGGGAACAGAAGAGAGAG AGAAGGTTCA GAACTCACAA GGACCCTTGG GTTAAGAGCC 1620 CGCCCCAAAGGTGAAAGCAC CCAGCAGAGT AGCCAATCCT GTGCCAGCGT CTTCAGCATC 1680 CCCACTCTGTGGAGTCCATG GCCACCCAGT AGCAGCTCCC AGCTCTAA 1728 1389 base pairs nucleicacid double linear cDNA 2 ATGAACCGGG GAGTCCCTTT TAGGCACTTG CTTCTGGTGCTGCAACTGGC GCTCCTCCCA 60 GCAGCCACTC AGGGAAACAA AGTGGTGCTG GGCAAAAAAGGGGATACAGT GGAACTGACC 120 TGTACAGCTT CCCAGAAGAA GAGCATACAA TTCCACTGGAAAAACTCCAA CCAGATAAAG 180 ATTCTGGGAA ATCAGGGCTC CTTCTTAACT AAAGGTCCATCCAAGCTGAA TGATCGCGCT 240 GACTCAAGAA GAAGCCTTTG GGACCAAGGA AACTTCCCCCTGATCATCAA GAATCTTAAG 300 ATAGAAGACT CAGATACTTA CATCTGTGAA GTGGAGGACCAGAAGGAGGA GGTGCAATTG 360 CTAGTGTTCG GATTGACTGC CAACTCTGAC ACCCACCTGCTTCAGGGGCA GAGCCTGACC 420 CTGACCTTGG AGAGCCCCCC TGGTAGTAGC CCCTCAGTGCAATGTAGGAG TCCAAGGGGT 480 AAAAACATAC AGGGGGGGAA GACCCTCTCC GTGTCTCAGCTGGAGCTCCA GGATAGTGGC 540 ACCTGGACAT GCACTGTCTT GCAGAACCAG AAGAAGGTGGAGTTCAAAAT AGACATCGTG 600 GTGCTAGCTT TCCAGAAGGC CTCCAGCATA GTCTATAAGAAAGAGGGGGA ACAGGTGGAG 660 TTCTCCTTCC CACTCGCCTT TACAGTTGAA AAGCTGACGGGCAGTGGCGA GCTGTGGTGG 720 CAGGCGGAGA GGGCTTCCTC CTCCAAGTCT TGGATCACCTTTGACCTGAA GAACAAGGAA 780 GTGTCTGTAA AACGGGTTAC CCAGGACCCT AAGCTCCAGATGGGCAAGAA GCTCCCGCTC 840 CACCTCACCC TGCCCCAGGC CTTGCCTCAG TATGCTGGCTCTGGAAACCT CACCCTGGCC 900 CTTGAAGCGA AAACAGGAAA GTTGCATCAG GAAGTGAACCTGGTGGTGAT GAGAGCCACT 960 CAGCTCCAGA AAAATTTGAC CTGTGAGGTG TGGGGACCCACCTCCCCTAA GCTGATGCTG 1020 AGCTTGAAAC TGGAGAACAA GGAGGCAAAG GTCTCGAAGCGGGAGAAGCC GGTGTGGGTG 1080 CTGAACCCTG AGGCGGGGAT GTGGCAGTGT CTGCTGAGTGACTCGGGACA GGTCCTGCTG 1140 GAATCCAACA TCAAGGTTCT GCCCACATGG TCCACCCCGGTGCACGCGGA TCCGCAGCTC 1200 TGCTATATCC TGGATGCCAT CCTGTTTTTG TATGGTATTGTCCTTACCCT GCTCTACTGT 1260 CGACTCAAGA TCCAGGTCCG AAAGGCAGAC ATAGCCAGCCGTGAGAAATC AGATGCTGTC 1320 TACACGGGCC TGAACACCCG GAACCAGGAG ACATATGAGACTCTGAAACA TGAGAAACCA 1380 CCCCAATAG 1389 1599 base pairs nucleic aciddouble linear cDNA 3 ATGAACCGGG GAGTCCCTTT TAGGCACTTG CTTCTGGTGCTGCAACTGGC GCTCCTCCCA 60 GCAGCCACTC AGGGAAACAA AGTGGTGCTG GGCAAAAAAGGGGATACAGT GGAACTGACC 120 TGTACAGCTT CCCAGAAGAA GAGCATACAA TTCCACTGGAAAAACTCCAA CCAGATAAAG 180 ATTCTGGGAA ATCAGGGCTC CTTCTTAACT AAAGGTCCATCCAAGCTGAA TGATCGCGCT 240 GACTCAAGAA GAAGCCTTTG GGACCAAGGA AACTTCCCCCTGATCATCAA GAATCTTAAG 300 ATAGAAGACT CAGATACTTA CATCTGTGAA GTGGAGGACCAGAAGGAGGA GGTGCAATTG 360 CTAGTGTTCG GATTGACTGC CAACTCTGAC ACCCACCTGCTTCAGGGGCA GAGCCTGACC 420 CTGACCTTGG AGAGCCCCCC TGGTAGTAGC CCCTCAGTGCAATGTAGGAG TCCAAGGGGT 480 AAAAACATAC AGGGGGGGAA GACCCTCTCC GTGTCTCAGCTGGAGCTCCA GGATAGTGGC 540 ACCTGGACAT GCACTGTCTT GCAGAACCAG AAGAAGGTGGAGTTCAAAAT AGACATCGTG 600 GTGCTAGCTT TCCAGAAGGC CTCCAGCATA GTCTATAAGAAAGAGGGGGA ACAGGTGGAG 660 TTCTCCTTCC CACTCGCCTT TACAGTTGAA AAGCTGACGGGCAGTGGCGA GCTGTGGTGG 720 CAGGCGGAGA GGGCTTCCTC CTCCAAGTCT TGGATCACCTTTGACCTGAA GAACAAGGAA 780 GTGTCTGTAA AACGGGTTAC CCAGGACCCT AAGCTCCAGATGGGCAAGAA GCTCCCGCTC 840 CACCTCACCC TGCCCCAGGC CTTGCCTCAG TATGCTGGCTCTGGAAACCT CACCCTGGCC 900 CTTGAAGCGA AAACAGGAAA GTTGCATCAG GAAGTGAACCTGGTGGTGAT GAGAGCCACT 960 CAGCTCCAGA AAAATTTGAC CTGTGAGGTG TGGGGACCCACCTCCCCTAA GCTGATGCTG 1020 AGCTTGAAAC TGGAGAACAA GGAGGCAAAG GTCTCGAAGCGGGAGAAGCC GGTGTGGGTG 1080 CTGAACCCTG AGGCGGGGAT GTGGCAGTGT CTGCTGAGTGACTCGGGACA GGTCCTGCTG 1140 GAATCCAACA TCAAGGTTCT GCCCACATGG TCCACCCCGGTGCACGCGGA TCCCAAACTC 1200 TGCTACCTGC TGGATGGAAT CCTCTTCATC TATGGTGTCATTCTCACTGC CTTGTTCCTG 1260 AGAGTGAAGT TCAGCAGGAG CGCAGAGCCC CCCGCGTACCAGCAGGGCCA GAACCAGCTC 1320 TATAACGAGC TCAATCTAGG ACGAAGAGAG GAGTACGATGTTTTGGACAA GAGACGTGGC 1380 CGGGACCCTG AGATGGGGGG AAAGCCGAGA AGGAAGAACCCTCAGGAAGG CCTGTACAAT 1440 GAACTGCAGA AAGATAAGAT GGCGGAGGCC TACAGTGAGATTGGGATGAA AGGCGAGCGC 1500 CGGAGGGGCA AGGGGCACGA TGGCCTTTAC CAGGGTCTCAGTACAGCCAC CAAGGACACC 1560 TACGACGCCC TTCACATGCA GGCCCTGCCC CCTCGCTAA1599 575 amino acids amino acid single linear protein 4 Met Asn Arg GlyVal Pro Phe Arg His Leu Leu Leu Val Leu Gln Leu 1 5 10 15 Ala Leu LeuPro Ala Ala Thr Gln Gly Asn Lys Val Val Leu Gly Lys 20 25 30 Lys Gly AspThr Val Glu Leu Thr Cys Thr Ala Ser Gln Lys Lys Ser 35 40 45 Ile Gln PheHis Trp Lys Asn Ser Asn Gln Ile Lys Ile Leu Gly Asn 50 55 60 Gln Gly SerPhe Leu Thr Lys Gly Pro Ser Lys Leu Asn Asp Arg Ala 65 70 75 80 Asp SerArg Arg Ser Leu Trp Asp Gln Gly Asn Phe Pro Leu Ile Ile 85 90 95 Lys AsnLeu Lys Ile Glu Asp Ser Asp Thr Tyr Ile Cys Glu Val Glu 100 105 110 AspGln Lys Glu Glu Val Gln Leu Leu Val Phe Gly Leu Thr Ala Asn 115 120 125Ser Asp Thr His Leu Leu Gln Gly Gln Ser Leu Thr Leu Thr Leu Glu 130 135140 Ser Pro Pro Gly Ser Ser Pro Ser Val Gln Cys Arg Ser Pro Arg Gly 145150 155 160 Lys Asn Ile Gln Gly Gly Lys Thr Leu Ser Val Ser Gln Leu GluLeu 165 170 175 Gln Asp Ser Gly Thr Trp Thr Cys Thr Val Leu Gln Asn GlnLys Lys 180 185 190 Val Glu Phe Lys Ile Asp Ile Val Val Leu Ala Phe GlnLys Ala Ser 195 200 205 Ser Ile Val Tyr Lys Lys Glu Gly Glu Gln Val GluPhe Ser Phe Pro 210 215 220 Leu Ala Phe Thr Val Glu Lys Leu Thr Gly SerGly Glu Leu Trp Trp 225 230 235 240 Gln Ala Glu Arg Ala Ser Ser Ser LysSer Trp Ile Thr Phe Asp Leu 245 250 255 Lys Asn Lys Glu Val Ser Val LysArg Val Thr Gln Asp Pro Lys Leu 260 265 270 Gln Met Gly Lys Lys Leu ProLeu His Leu Thr Leu Pro Gln Ala Leu 275 280 285 Pro Gln Tyr Ala Gly SerGly Asn Leu Thr Leu Ala Leu Glu Ala Lys 290 295 300 Thr Gly Lys Leu HisGln Glu Val Asn Leu Val Val Met Arg Ala Thr 305 310 315 320 Gln Leu GlnLys Asn Leu Thr Cys Glu Val Trp Gly Pro Thr Ser Pro 325 330 335 Lys LeuMet Leu Ser Leu Lys Leu Glu Asn Lys Glu Ala Lys Val Ser 340 345 350 LysArg Glu Lys Pro Val Trp Val Leu Asn Pro Glu Ala Gly Met Trp 355 360 365Gln Cys Leu Leu Ser Asp Ser Gly Gln Val Leu Leu Glu Ser Asn Ile 370 375380 Lys Val Leu Pro Thr Trp Ser Thr Pro Val His Ala Asp Pro Lys Leu 385390 395 400 Cys Tyr Leu Leu Asp Gly Ile Leu Phe Ile Tyr Gly Val Ile IleThr 405 410 415 Ala Leu Tyr Leu Arg Ala Lys Phe Ser Arg Ser Ala Glu ThrAla Ala 420 425 430 Asn Leu Gln Asp Pro Asn Gln Leu Tyr Asn Glu Leu AsnLeu Gly Arg 435 440 445 Arg Glu Glu Tyr Asp Val Leu Glu Lys Lys Arg AlaArg Asp Pro Glu 450 455 460 Met Gly Gly Lys Gln Gln Arg Arg Arg Asn ProGln Glu Gly Val Tyr 465 470 475 480 Asn Ala Leu Gln Lys Asp Lys Met ProGlu Ala Tyr Ser Glu Ile Gly 485 490 495 Thr Lys Gly Glu Arg Arg Arg GlyLys Gly His Asp Gly Leu Tyr Gln 500 505 510 Asp Ser His Phe Gln Ala ValGln Phe Gly Asn Arg Arg Glu Arg Glu 515 520 525 Gly Ser Glu Leu Thr ArgThr Leu Gly Leu Arg Ala Arg Pro Lys Gly 530 535 540 Glu Ser Thr Gln GlnSer Ser Gln Ser Cys Ala Ser Val Phe Ser Ile 545 550 555 560 Pro Thr LeuTrp Ser Pro Trp Pro Pro Ser Ser Ser Ser Gln Leu 565 570 575 462 aminoacids amino acid single linear protein 5 Met Asn Arg Gly Val Pro Phe ArgHis Leu Leu Leu Val Leu Gln Leu 1 5 10 15 Ala Leu Leu Pro Ala Ala ThrGln Gly Asn Lys Val Val Leu Gly Lys 20 25 30 Lys Gly Asp Thr Val Glu LeuThr Cys Thr Ala Ser Gln Lys Lys Ser 35 40 45 Ile Gln Phe His Trp Lys AsnSer Asn Gln Ile Lys Ile Leu Gly Asn 50 55 60 Gln Gly Ser Phe Leu Thr LysGly Pro Ser Lys Leu Asn Asp Arg Ala 65 70 75 80 Asp Ser Arg Arg Ser LeuTrp Asp Gln Gly Asn Phe Pro Leu Ile Ile 85 90 95 Lys Asn Leu Lys Ile GluAsp Ser Asp Thr Tyr Ile Cys Glu Val Glu 100 105 110 Asp Gln Lys Glu GluVal Gln Leu Leu Val Phe Gly Leu Thr Ala Asn 115 120 125 Ser Asp Thr HisLeu Leu Gln Gly Gln Ser Leu Thr Leu Thr Leu Glu 130 135 140 Ser Pro ProGly Ser Ser Pro Ser Val Gln Cys Arg Ser Pro Arg Gly 145 150 155 160 LysAsn Ile Gln Gly Gly Lys Thr Leu Ser Val Ser Gln Leu Glu Leu 165 170 175Gln Asp Ser Gly Thr Trp Thr Cys Thr Val Leu Gln Asn Gln Lys Lys 180 185190 Val Glu Phe Lys Ile Asp Ile Val Val Leu Ala Phe Gln Lys Ala Ser 195200 205 Ser Ile Val Tyr Lys Lys Glu Gly Glu Gln Val Glu Phe Ser Phe Pro210 215 220 Leu Ala Phe Thr Val Glu Lys Leu Thr Gly Ser Gly Glu Leu TrpTrp 225 230 235 240 Gln Ala Glu Arg Ala Ser Ser Ser Lys Ser Trp Ile ThrPhe Asp Leu 245 250 255 Lys Asn Lys Glu Val Ser Val Lys Arg Val Thr GlnAsp Pro Lys Leu 260 265 270 Gln Met Gly Lys Lys Leu Pro Leu His Leu ThrLeu Pro Gln Ala Leu 275 280 285 Pro Gln Tyr Ala Gly Ser Gly Asn Leu ThrLeu Ala Leu Glu Ala Lys 290 295 300 Thr Gly Lys Leu His Gln Glu Val AsnLeu Val Val Met Arg Ala Thr 305 310 315 320 Gln Leu Gln Lys Asn Leu ThrCys Glu Val Trp Gly Pro Thr Ser Pro 325 330 335 Lys Leu Met Leu Ser LeuLys Leu Glu Asn Lys Glu Ala Lys Val Ser 340 345 350 Lys Arg Glu Lys ProVal Trp Val Leu Asn Pro Glu Ala Gly Met Trp 355 360 365 Gln Cys Leu LeuSer Asp Ser Gly Gln Val Leu Leu Glu Ser Asn Ile 370 375 380 Lys Val LeuPro Thr Trp Ser Thr Pro Val His Ala Asp Pro Gln Leu 385 390 395 400 CysTyr Ile Leu Asp Ala Ile Leu Phe Leu Tyr Gly Ile Val Leu Thr 405 410 415Leu Leu Tyr Cys Arg Leu Lys Ile Gln Val Arg Lys Ala Asp Ile Ala 420 425430 Ser Arg Glu Lys Ser Asp Ala Val Tyr Thr Gly Leu Asn Thr Arg Asn 435440 445 Gln Glu Thr Tyr Glu Thr Leu Lys His Glu Lys Pro Pro Gln 450 455460 532 amino acids amino acid single linear protein 6 Met Asn Arg GlyVal Pro Phe Arg His Leu Leu Leu Val Leu Gln Leu 1 5 10 15 Ala Leu LeuPro Ala Ala Thr Gln Gly Asn Lys Val Val Leu Gly Lys 20 25 30 Lys Gly AspThr Val Glu Leu Thr Cys Thr Ala Ser Gln Lys Lys Ser 35 40 45 Ile Gln PheHis Trp Lys Asn Ser Asn Gln Ile Lys Ile Leu Gly Asn 50 55 60 Gln Gly SerPhe Leu Thr Lys Gly Pro Ser Lys Leu Asn Asp Arg Ala 65 70 75 80 Asp SerArg Arg Ser Leu Trp Asp Gln Gly Asn Phe Pro Leu Ile Ile 85 90 95 Lys AsnLeu Lys Ile Glu Asp Ser Asp Thr Tyr Ile Cys Glu Val Glu 100 105 110 AspGln Lys Glu Glu Val Gln Leu Leu Val Phe Gly Leu Thr Ala Asn 115 120 125Ser Asp Thr His Leu Leu Gln Gly Gln Ser Leu Thr Leu Thr Leu Glu 130 135140 Ser Pro Pro Gly Ser Ser Pro Ser Val Gln Cys Arg Ser Pro Arg Gly 145150 155 160 Lys Asn Ile Gln Gly Gly Lys Thr Leu Ser Val Ser Gln Leu GluLeu 165 170 175 Gln Asp Ser Gly Thr Trp Thr Cys Thr Val Leu Gln Asn GlnLys Lys 180 185 190 Val Glu Phe Lys Ile Asp Ile Val Val Leu Ala Phe GlnLys Ala Ser 195 200 205 Ser Ile Val Tyr Lys Lys Glu Gly Glu Gln Val GluPhe Ser Phe Pro 210 215 220 Leu Ala Phe Thr Val Glu Lys Leu Thr Gly SerGly Glu Leu Trp Trp 225 230 235 240 Gln Ala Glu Arg Ala Ser Ser Ser LysSer Trp Ile Thr Phe Asp Leu 245 250 255 Lys Asn Lys Glu Val Ser Val LysArg Val Thr Gln Asp Pro Lys Leu 260 265 270 Gln Met Gly Lys Lys Leu ProLeu His Leu Thr Leu Pro Gln Ala Leu 275 280 285 Pro Gln Tyr Ala Gly SerGly Asn Leu Thr Leu Ala Leu Glu Ala Lys 290 295 300 Thr Gly Lys Leu HisGln Glu Val Asn Leu Val Val Met Arg Ala Thr 305 310 315 320 Gln Leu GlnLys Asn Leu Thr Cys Glu Val Trp Gly Pro Thr Ser Pro 325 330 335 Lys LeuMet Leu Ser Leu Lys Leu Glu Asn Lys Glu Ala Lys Val Ser 340 345 350 LysArg Glu Lys Pro Val Trp Val Leu Asn Pro Glu Ala Gly Met Trp 355 360 365Gln Cys Leu Leu Ser Asp Ser Gly Gln Val Leu Leu Glu Ser Asn Ile 370 375380 Lys Val Leu Pro Thr Trp Ser Thr Pro Val His Ala Asp Pro Lys Leu 385390 395 400 Cys Tyr Leu Leu Asp Gly Ile Leu Phe Ile Tyr Gly Val Ile LeuThr 405 410 415 Ala Leu Phe Leu Arg Val Lys Phe Ser Arg Ser Ala Glu ProPro Ala 420 425 430 Tyr Gln Gln Gly Gln Asn Gln Leu Tyr Asn Glu Leu AsnLeu Gly Arg 435 440 445 Arg Glu Glu Tyr Asp Val Leu Asp Lys Arg Arg GlyArg Asp Pro Glu 450 455 460 Met Gly Gly Lys Pro Arg Arg Lys Asn Pro GlnGlu Gly Leu Tyr Asn 465 470 475 480 Glu Leu Gln Lys Asp Lys Met Ala GluAla Tyr Ser Glu Ile Gly Met 485 490 495 Lys Gly Glu Arg Arg Arg Gly LysGly His Asp Gly Leu Tyr Gln Gly 500 505 510 Leu Ser Thr Ala Thr Lys AspThr Tyr Asp Ala Leu His Met Gln Ala 515 520 525 Leu Pro Pro Arg 530 33base pairs nucleic acid single linear Other 7 CGCGGGGTGA CCGTGCCCTCCAGCAGCTTG GGC 33 50 base pairs nucleic acid single linear Other 8CGCGGGGATC CGTCGTCCAG AGCCCGTCCA GCTCCCCGTC CTGGGCCTCA 50 33 base pairsnucleic acid single linear Other 9 CGCGGGCGGC CGCGACGCCG GCCAAGACAG CAC33 33 base pairs nucleic acid single linear Other 10 CGCGTTGACGAGCAGCCAGT TGGGCAGCAG CAG 33 15 base pairs nucleic acid single linearOther 11 CGCGGGCGGC CGCTA 15 42 base pairs nucleic acid single linearOther 12 CGCGGGCTCG TTATAGAGCT GGTTCTGGCG CTGCTTCTTC TG 42 48 base pairsnucleic acid single linear Other 13 CGCGGGGAGC TCGTTATAGA GCTGGTTTGCCGCCGAATTC TTATCCCG 48 33 base pairs nucleic acid single linear Other 14CGCGGGGCGG CCACGCGTCC TCGCCAGCAC ACA 33 36 base pairs nucleic acidsingle linear Other 15 CGCGGGACGC GTTTCAGCCG TCCTCGCCAG CACACA 36 33base pairs nucleic acid single linear Other 16 CGCGGGACGC GTGACCCTGAGATGGGGGGA AAG 33 33 base pairs nucleic acid single linear Other 17CGCGGGACGC GTATTGGGAT GAAAGGCGAG CGC 33 26 base pairs nucleic acidsingle linear Other 18 CCCGGATCCC AGCATGGGCA GCTCTT 26 42 base pairsnucleic acid single linear Other 19 CGCGGGGCGG CCGCTTTAGT TATTACTGTTGACATGGTCG TT 42 40 base pairs nucleic acid single linear Other 20GCGGGGGGAT CCCACTGTCC AAGCTCCCAG CTCTTCACCG 40 32 base pairs nucleicacid single linear Other 21 GCGGGGGCGG CCGCCTAAAT ACGGTTCTGG TC 32 31base pairs nucleic acid single linear Other 22 TCAGAAAGAG ACAACCTGAAGAAACCAACA A 31 31 base pairs nucleic acid single linear Other 23TTGTTGGTTT CTTCAGGTTG TGTCTTTCTG A 31 171 amino acids amino acid singlelinear protein 24 Met Glu His Ser Thr Phe Leu Ser Gly Leu Val Leu AlaThr Leu Leu 1 5 10 15 Ser Gln Val Ser Pro Phe Lys Ile Pro Ile Glu GluLeu Glu Asp Arg 20 25 30 Val Phe Val Asn Cys Asn Thr Ser Ile Thr Trp ValGlu Gly Thr Val 35 40 45 Gly Thr Leu Leu Ser Asp Ile Thr Arg Leu Asp LeuGly Lys Arg Ile 50 55 60 Leu Asp Pro Arg Gly Ile Tyr Arg Cys Asn Gly ThrAsp Ile Tyr Lys 65 70 75 80 Asp Lys Glu Ser Thr Val Gln Val His Tyr ArgMet Cys Gln Ser Cys 85 90 95 Val Glu Leu Asp Pro Ala Thr Val Ala Gly IleIle Val Thr Asp Val 100 105 110 Ala Ile Thr Leu Leu Leu Ala Leu Gly ValPhe Cys Phe Ala Gly His 115 120 125 Glu Thr Gly Arg Leu Ser Gly Ala AlaAsp Thr Gln Ala Leu Leu Arg 130 135 140 Asn Asp Gln Val Tyr Gln Pro LeuArg Asp Arg Asp Asp Ala Gln Tyr 145 150 155 160 Ser His Leu Gly Gly AsnTrp Ala Arg Asn Lys 165 170 182 amino acids amino acid single linearprotein 25 Met Glu Gln Gly Lys Gly Leu Ala Val Leu Ile Leu Ala Ile IleLeu 1 5 10 15 Leu Gln Gly Thr Leu Ala Gln Ser Ile Lys Gly Asn His LeuVal Lys 20 25 30 Val Tyr Asp Tyr Gln Glu Asp Gly Ser Val Leu Leu Thr CysAsp Ala 35 40 45 Glu Ala Lys Asn Ile Thr Trp Phe Lys Asp Gly Lys Met IleGly Phe 50 55 60 Leu Thr Glu Asp Lys Lys Lys Trp Asn Leu Gly Ser Asn AlaLys Asp 65 70 75 80 Pro Arg Gly Met Tyr Gln Cys Lys Gly Ser Gln Asn LysSer Lys Pro 85 90 95 Leu Gln Val Tyr Tyr Arg Met Cys Gln Asn Cys Ile GluLeu Asn Ala 100 105 110 Ala Thr Ile Ser Gly Phe Leu Phe Ala Glu Ile ValSer Ile Phe Val 115 120 125 Leu Ala Val Gly Val Tyr Phe Ile Ala Gly GlnAsp Gly Val Arg Gln 130 135 140 Ser Arg Ala Ser Asp Lys Gln Thr Leu LeuPro Asn Asp Gln Leu Tyr 145 150 155 160 Gln Pro Leu Lys Asp Arg Glu AspAsp Gln Tyr Ser His Leu Gln Gly 165 170 175 Asn Gln Leu Arg Arg Asn 180220 amino acids amino acid single linear protein 26 Met Pro Gly Gly LeuGlu Ala Leu Arg Ala Leu Pro Leu Leu Leu Phe 1 5 10 15 Leu Ser Tyr AlaCys Leu Gly Pro Gly Cys Gln Ala Leu Arg Val Glu 20 25 30 Gly Gly Pro ProSer Leu Thr Val Asn Leu Gly Glu Glu Ala Arg Leu 35 40 45 Thr Cys Glu AsnAsn Gly Arg Asn Pro Asn Ile Thr Trp Trp Phe Ser 50 55 60 Leu Gln Ser AsnIle Thr Trp Pro Pro Val Pro Leu Gly Pro Gly Gln 65 70 75 80 Gly Thr ThrGly Gln Leu Phe Phe Pro Glu Val Asn Lys Asn Thr Gly 85 90 95 Ala Cys ThrGly Cys Gln Val Ile Glu Asn Asn Ile Leu Lys Arg Ser 100 105 110 Cys GlyThr Tyr Leu Arg Val Arg Asn Pro Val Pro Arg Pro Phe Leu 115 120 125 AspMet Gly Glu Gly Thr Lys Asn Arg Ile Ile Thr Ala Glu Gly Ile 130 135 140Ile Leu Leu Phe Cys Ala Val Val Pro Gly Thr Leu Leu Leu Phe Arg 145 150155 160 Lys Arg Trp Gln Asn Glu Lys Phe Gly Val Asp Met Pro Asp Asp Tyr165 170 175 Glu Asp Glu Asn Leu Tyr Glu Gly Leu Asn Leu Asp Asp Cys SerMet 180 185 190 Tyr Glu Asp Ile Ser Arg Gly Leu Gln Gly Thr Tyr Gln AspVal Gly 195 200 205 Asn Leu His Ile Gly Asp Ala Gln Leu Glu Lys Pro 210215 220 228 amino acids amino acid single linear protein 27 Met Ala ThrLeu Val Leu Ser Ser Met Pro Cys His Trp Leu Leu Phe 1 5 10 15 Leu LeuLeu Leu Phe Ser Gly Glu Pro Val Pro Ala Met Thr Ser Ser 20 25 30 Asp LeuPro Leu Asn Phe Gln Gly Ser Pro Cys Ser Gln Ile Trp Gln 35 40 45 His ProArg Phe Ala Ala Lys Lys Arg Ser Ser Met Val Lys Phe His 50 55 60 Cys TyrThr Asn His Ser Gly Ala Leu Thr Trp Phe Arg Lys Arg Gly 65 70 75 80 SerGln Gln Pro Gln Glu Leu Val Ser Glu Glu Gly Arg Ile Val Gln 85 90 95 ThrGln Asn Gly Ser Val Tyr Thr Leu Thr Ile Gln Asn Ile Gln Tyr 100 105 110Glu Asp Asn Gly Ile Tyr Phe Cys Lys Gln Lys Cys Asp Ser Ala Asn 115 120125 His Asn Val Thr Asp Ser Cys Gly Thr Glu Leu Leu Val Leu Gly Phe 130135 140 Ser Thr Leu Asp Gln Leu Lys Arg Arg Asn Thr Leu Lys Asp Gly Ile145 150 155 160 Ile Leu Ile Gln Thr Leu Leu Ile Ile Leu Phe Ile Ile ValPro Ile 165 170 175 Phe Leu Leu Leu Asp Lys Asp Asp Gly Lys Ala Gly MetGlu Glu Asp 180 185 190 His Thr Tyr Glu Gly Leu Asn Ile Asp Gln Thr AlaThr Tyr Glu Asp 195 200 205 Ile Val Thr Leu Arg Thr Gly Glu Val Lys TrpSer Val Gly Glu His 210 215 220 Pro Gly Gln Glu 225 1304 base pairsnucleic acid single linear cDNA 28 GCCTGTTTGA GAAGCAGCGG GCAAGAAAGACGCAAGCCCA GAGGCCCTGC CATTTCTGTG 60 GGCTCAGGTC CCTACTGGCT CAGGCCCCTGCCTCCCTCGG CAAGGCCACA ATGAACCGGG 120 GAGTCCCTTT TAGGCACTTG CTTCTGGTGCTGCAACTGGC GCTCCTCCCA GCAGCCACTC 180 AGGGAAACAA AGTGGTGCTG GGCAAAAAAGGGGATACAGT GGAACTGACC TGTACAGCTT 240 CCCAGAAGAA GAGCATACAA TTCCACTGGAAAAACTCCAA CCAGATAAAG ATTCTGGGAA 300 ATCAGGGCTC CTTCTTAACT AAAGGTCCATCCAAGCTGAA TGATCGCGCT GACTCAAGAA 360 GAAGCCTTTG GGACCAAGGA AACTTCCCCCTGATCATCAA GAATCTTAAG ATAGAAGACT 420 CAGATACTTA CATCTGTGAA GTGGAGGACCAGAAGGAGGA GGTGCAATTG CTAGTGTTCG 480 GATTGACTGC CAACTCTGAC ACCCACCTGCTTCAGGGGCA GAGCCTGACC CTGACCTTGG 540 AGAGCCCCCC TGGTAGTAGC CCCTCAGTGCAATGTAGGAG TCCAAGGGGT AAAAACATAC 600 AGGGGGGGAA GACCCTCTCC GTGTCTCAGCTGGAGCTCCA GGATAGTGGC ACCTGGACAT 660 GCACTGTCTT GCAGAACCAG AAGAAGGTGGAGTTCAAAAT AGACATCGTG GTGCTAGCTT 720 TCCAGAAGGC CTCCAGCATA GTCTATAAGAAAGAGGGGGA ACAGGTGGAG TTCTCCTTCC 780 CACTCGCCTT TACAGTTGAA AAGCTGACGGGCAGTGGCGA GCTGTGGTGG CAGGCGGAGA 840 GGGCTTCCTC CTCCAAGTCT TGGATCACCTTTGACCTGAA GAACAAGGAA GTGTCTGTAA 900 AACGGGTTAC CCAGGACCCT AAGCTCCAGATGGGCAAGAA GCTCCCGCTC CACCTCACCC 960 TGCCCCAGGC CTTGCCTCAG TATGCTGGCTCTGGAAACCT CACCCTGGCC CTTGAAGCGA 1020 AAACAGGAAA GTTGCATCAG GAAGTGAACCTGGTGGTGAT GAGAGCCACT CAGCTCCAGA 1080 AAAATTTGAC CTGTGAGGTG TGGGGACCCACCTCCCCTAA GCTGATGCTG AGCTTGAAAC 1140 TGGAGAACAA GGAGGCAAAG GTCTCGAAGCGGGAGAAGCC GGTGTGGGTG CTGAACCCTG 1200 AGGCGGGGAT GTGGCAGTGT CTGCTGAGTGACTCGGGACA GGTCCTGCTG GAATCCAACA 1260 TCAAGGTTCT GCCCACATGG TCCACCCCGGTGCACGCGGA TCCC 1304 398 amino acids amino acid single linear protein 29Met Asn Arg Gly Val Pro Phe Arg His Leu Leu Leu Val Leu Gln Leu 1 5 1015 Ala Leu Leu Pro Ala Ala Thr Gln Gly Asn Lys Val Val Leu Gly Lys 20 2530 Lys Gly Asp Thr Val Glu Leu Thr Cys Thr Ala Ser Gln Lys Lys Ser 35 4045 Ile Gln Phe His Trp Lys Asn Ser Asn Gln Ile Lys Ile Leu Gly Asn 50 5560 Gln Gly Ser Phe Leu Thr Lys Gly Pro Ser Lys Leu Asn Asp Arg Ala 65 7075 80 Asp Ser Arg Arg Ser Leu Trp Asp Gln Gly Asn Phe Pro Leu Ile Ile 8590 95 Lys Asn Leu Lys Ile Glu Asp Ser Asp Thr Tyr Ile Cys Glu Val Glu100 105 110 Asp Gln Lys Glu Glu Val Gln Leu Leu Val Phe Gly Leu Thr AlaAsn 115 120 125 Ser Asp Thr His Leu Leu Gln Gly Gln Ser Leu Thr Leu ThrLeu Glu 130 135 140 Ser Pro Pro Gly Ser Ser Pro Ser Val Gln Cys Arg SerPro Arg Gly 145 150 155 160 Lys Asn Ile Gln Gly Gly Lys Thr Leu Ser ValSer Gln Leu Glu Leu 165 170 175 Gln Asp Ser Gly Thr Trp Thr Cys Thr ValLeu Gln Asn Gln Lys Lys 180 185 190 Val Glu Phe Lys Ile Asp Ile Val ValLeu Ala Phe Gln Lys Ala Ser 195 200 205 Ser Ile Val Tyr Lys Lys Glu GlyGlu Gln Val Glu Phe Ser Phe Pro 210 215 220 Leu Ala Phe Thr Val Glu LysLeu Thr Gly Ser Gly Glu Leu Trp Trp 225 230 235 240 Gln Ala Glu Arg AlaSer Ser Ser Lys Ser Trp Ile Thr Phe Asp Leu 245 250 255 Lys Asn Lys GluVal Ser Val Lys Arg Val Thr Gln Asp Pro Lys Leu 260 265 270 Gln Met GlyLys Lys Leu Pro Leu His Leu Thr Leu Pro Gln Ala Leu 275 280 285 Pro GlnTyr Ala Gly Ser Gly Asn Leu Thr Leu Ala Leu Glu Ala Lys 290 295 300 ThrGly Lys Leu His Gln Glu Val Asn Leu Val Val Met Arg Ala Thr 305 310 315320 Gln Leu Gln Lys Asn Leu Thr Cys Glu Val Trp Gly Pro Thr Ser Pro 325330 335 Lys Leu Met Leu Ser Leu Lys Leu Glu Asn Lys Glu Ala Lys Val Ser340 345 350 Lys Arg Glu Lys Pro Val Trp Val Leu Asn Pro Glu Ala Gly MetTrp 355 360 365 Gln Cys Leu Leu Ser Asp Ser Gly Gln Val Leu Leu Glu SerAsn Ile 370 375 380 Lys Val Leu Pro Thr Trp Ser Thr Pro Val His Ala AspPro 385 390 395 719 base pairs nucleic acid single linear cDNA 30GCCTGTTTGA GAAGCAGCGG GCAAGAAAGA CGCAAGCCCA GAGGCCCTGC CATTTCTGTG 60GGCTCAGGTC CCTACTGGCT CAGGCCCCTG CCTCCCTCGG CAAGGCCACA ATGAACCGGG 120GAGTCCCTTT TAGGCACTTG CTTCTGGTGC TGCAACTGGC GCTCCTCCCA GCAGCCACTC 180AGGGAAACAA AGTGGTGCTG GGCAAAAAAG GGGATACAGT GGAACTGACC TGTACAGCTT 240CCCAGAAGAA GAGCATACAA TTCCACTGGA AAAACTCCAA CCAGATAAAG ATTCTGGGAA 300ATCAGGGCTC CTTCTTAACT AAAGGTCCAT CCAAGCTGAA TGATCGCGCT GACTCAAGAA 360GAAGCCTTTG GGACCAAGGA AACTTCCCCC TGATCATCAA GAATCTTAAG ATAGAAGACT 420CAGATACTTA CATCTGTGAA GTGGAGGACC AGAAGGAGGA GGTGCAATTG CTAGTGTTCG 480GATTGACTGC CAACTCTGAC ACCCACCTGC TTCAGGGGCA GAGCCTGACC CTGACCTTGG 540AGAGCCCCCC TGGTAGTAGC CCCTCAGTGC AATGTAGGAG TCCAAGGGGT AAAAACATAC 600AGGGGGGGAA GACCCTCTCC GTGTCTCAGC TGGAGCTCCA GGATAGTGGC ACCTGGACAT 660GCACTGTCTT GCAGAACCAG AAGAAGGTGG AGTTCAAAAT AGACATCGTG GTGCTAGCT 719 203amino acids amino acid single linear protein 31 Met Asn Arg Gly Val ProPhe Arg His Leu Leu Leu Val Leu Gln Leu 1 5 10 15 Ala Leu Leu Pro AlaAla Thr Gln Gly Asn Lys Val Val Leu Gly Lys 20 25 30 Lys Gly Asp Thr ValGlu Leu Thr Cys Thr Ala Ser Gln Lys Lys Ser 35 40 45 Ile Gln Phe His TrpLys Asn Ser Asn Gln Ile Lys Ile Leu Gly Asn 50 55 60 Gln Gly Ser Phe LeuThr Lys Gly Pro Ser Lys Leu Asn Asp Arg Ala 65 70 75 80 Asp Ser Arg ArgSer Leu Trp Asp Gln Gly Asn Phe Pro Leu Ile Ile 85 90 95 Lys Asn Leu LysIle Glu Asp Ser Asp Thr Tyr Ile Cys Glu Val Glu 100 105 110 Asp Gln LysGlu Glu Val Gln Leu Leu Val Phe Gly Leu Thr Ala Asn 115 120 125 Ser AspThr His Leu Leu Gln Gly Gln Ser Leu Thr Leu Thr Leu Glu 130 135 140 SerPro Pro Gly Ser Ser Pro Ser Val Gln Cys Arg Ser Pro Arg Gly 145 150 155160 Lys Asn Ile Gln Gly Gly Lys Thr Leu Ser Val Ser Gln Leu Glu Leu 165170 175 Gln Asp Ser Gly Thr Trp Thr Cys Thr Val Leu Gln Asn Gln Lys Lys180 185 190 Val Glu Phe Lys Ile Asp Ile Val Val Leu Ala 195 200 768 basepairs nucleic acid single linear cDNA 32 GCTAGCAGAG CCCAAATCTTGTGACAAAAC TCACACATGC CCACCGTGCC CAGCACCTGA 60 ACTCCTGGGG GGACCGTCAGTCTTCCTCTT CCCCCCAAAA CCCAAGGACA CCCTCATGAT 120 CTCCCGGACC CCTGAGGTCACATGCGTGGT GGTGGACGTG AGCCACGAAG ACCCTGAGGT 180 CAAGTTCAAC TGGTACGTGGACGGCGTGGA GGTGCATAAT GCCAAGACAA AGCCGCGGGA 240 GGAGCAGTAC AACAGCACGTACCGGGTGGT CAGCGTCCTC ACCGTCCTGC ACCAGGACTG 300 GCTGAATGGC AAGGAGTACAAGTGCAAGGT CTCCAACAAA GCCCTCCCAG CCCCCATCGA 360 GAAAACCATC TCCAAAGCCAAAGGGCAGCC CCGAGAACCA CAGGTGTACA CCCTGCCCCC 420 ATCCCGGGAT GAGCTGACCAAGAACCAGGT CAGCCTGACC TGCCTGGTCA AAGGCTTCTA 480 TCCCAGCGAC ATCGCCGTGGAGTGGGAGAG CAATGGGCAG CCGGAGAACA ACTACAAGAC 540 CACGCCTCCC GTGCTGGACTCCGACGGCTC CTTCTTCCTC TACAGCAAGC TCACCGTGGA 600 CAAGAGCAGG TGGCAGCAGGGGAACGTCTT CTCATGCTCC GTGATGCATG AGGCTCTGCA 660 CAACCACTAC ACGCAGAAGAGCCTCTCCCT GTCTCCGGGG CTGCAACTGG ACGAGACCTG 720 TGCTGAGGCC CAGGACGGGGAGCTGGACGG GCTCTGGACG ACGGATCC 768 254 amino acids amino acid singlelinear protein 33 Glu Pro Lys Ser Cys Asp Lys Thr His Thr Cys Pro ProCys Pro Ala 1 5 10 15 Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu PhePro Pro Lys Pro 20 25 30 Lys Asp Thr Leu Met Ile Ser Arg Thr Pro Glu ValThr Cys Val Val 35 40 45 Val Asp Val Ser His Glu Asp Pro Glu Val Lys PheAsn Trp Tyr Val 50 55 60 Asp Gly Val Glu Val His Asn Ala Lys Thr Lys ProArg Glu Glu Gln 65 70 75 80 Tyr Asn Ser Thr Tyr Arg Val Val Ser Val LeuThr Val Leu His Gln 85 90 95 Asp Trp Leu Asn Gly Lys Glu Tyr Lys Cys LysVal Ser Asn Lys Ala 100 105 110 Leu Pro Ala Pro Ile Glu Lys Thr Ile SerLys Ala Lys Gly Gln Pro 115 120 125 Arg Glu Pro Gln Val Tyr Thr Leu ProPro Ser Arg Asp Glu Leu Thr 130 135 140 Lys Asn Gln Val Ser Leu Thr CysLeu Val Lys Gly Phe Tyr Pro Ser 145 150 155 160 Asp Ile Ala Val Glu TrpGlu Ser Asn Gly Gln Pro Glu Asn Asn Tyr 165 170 175 Lys Thr Thr Pro ProVal Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr 180 185 190 Ser Lys Leu ThrVal Asp Lys Ser Arg Trp Gln Gln Gly Asn Val Phe 195 200 205 Ser Cys SerVal Met His Glu Ala Leu His Asn His Tyr Thr Gln Lys 210 215 220 Ser LeuSer Leu Ser Pro Gly Leu Gln Leu Asp Glu Thr Cys Ala Glu 225 230 235 240Ala Gln Asp Gly Glu Leu Asp Gly Leu Trp Thr Thr Asp Pro 245 250 174 basepairs nucleic acid single linear cDNA 34 CCAAGGGCCT CTGCCCTCCCTGCCCCACCG ACAGGCTCCG CCCTCCCTGA CCCGCAGACA 60 GCCTCTGCCC TCCCTGACCCGCCAGCAGCC TCTGCCCTCC CTGCGGCCCT GGCGGTGATC 120 TCCTTCCTCC TCGGGCTGGGCCTGGGGGTG GCGTGTGTGC TGGCGAGGAC GCGT 174 58 amino acids amino acidsingle linear protein 35 Pro Arg Ala Ser Ala Leu Pro Ala Pro Pro Thr GlySer Ala Leu Pro 1 5 10 15 Asp Pro Gln Thr Ala Ser Ala Leu Pro Asp ProPro Ala Ala Ser Ala 20 25 30 Leu Pro Ala Ala Leu Ala Val Ile Ser Phe LeuLeu Gly Leu Gly Leu 35 40 45 Gly Val Ala Cys Val Leu Ala Arg Thr Arg 5055 345 base pairs nucleic acid single linear cDNA 36 ACGCGTTTCAGCAGGAGCGC AGAGCCCCCC GCGTACCAGC AGGGCCAGAA CCAGCTCTAT 60 AACGAGCTCAATCTAGGACG AAGAGAGGAG TACGATGTTT TGGACAAGAG ACGTGGCCGG 120 GACCCTGAGATGGGGGGAAA GCCGAGAAGG AAGAACCCTC AGGAAGGCCT GTACAATGAA 180 CTGCAGAAAGATAAGATGGC GGAGGCCTAC AGTGAGATTG GGATGAAAGG CGAGCGCCGG 240 AGGGGCAAGGGGCACGATGG CCTTTACCAG GGTCTCAGTA CAGCCACCAA GGACACCTAC 300 GACGCCCTTCACATGCAGGC CCTGCCCCCT CGCTAAAGCG GCCGC 345 111 amino acids amino acidsingle linear protein 37 Thr Arg Phe Ser Arg Ser Ala Glu Pro Pro Ala TyrGln Gln Gly Gln 1 5 10 15 Asn Gln Leu Tyr Asn Glu Leu Asn Leu Gly ArgArg Glu Glu Tyr Asp 20 25 30 Val Leu Asp Lys Arg Arg Gly Arg Asp Pro GluMet Gly Gly Lys Pro 35 40 45 Arg Arg Lys Asn Pro Gln Glu Gly Leu Tyr AsnGlu Leu Gln Lys Asp 50 55 60 Lys Met Ala Glu Ala Tyr Ser Glu Ile Gly MetLys Gly Glu Arg Arg 65 70 75 80 Arg Gly Lys Gly His Asp Gly Leu Tyr GlnGly Leu Ser Thr Ala Thr 85 90 95 Lys Asp Thr Tyr Asp Ala Leu His Met GlnAla Leu Pro Pro Arg 100 105 110 16 amino acids amino acid unknown linearprotein 38 Gln Ser Phe Gly Leu Leu Asp Pro Lys Leu Cys Tyr Leu Leu AspGly 1 5 10 15 19 amino acids amino acid unknown linear protein 39 ProThr Trp Ser Thr Pro Val His Ala Asp Pro Lys Leu Cys Tyr Leu 1 5 10 15Leu Asp Gly 12 amino acids amino acid unknown linear protein 40 Leu GlyGlu Pro Gln Leu Cys Tyr Ile Leu Asp Ala 1 5 10 19 amino acids amino acidunknown linear protein 41 Pro Thr Trp Ser Thr Pro Val His Ala Asp ProGln Leu Cys Tyr Ile 1 5 10 15 Leu Asp Ala 16 amino acids amino acidunknown linear protein 42 Gln Ser Phe Gly Leu Leu Asp Pro Lys Leu CysTyr Leu Leu Asp Gly 1 5 10 15 16 amino acids amino acid unknown linearprotein 43 Phe Ser Pro Pro Gly Ala Asp Pro Lys Leu Cys Tyr Leu Leu AspGly 1 5 10 15 142 amino acids amino acid unknown linear protein 44 GlnSer Phe Gly Leu Leu Asp Pro Lys Leu Cys Tyr Leu Leu Asp Gly 1 5 10 15Ile Leu Phe Ile Tyr Gly Val Ile Leu Thr Ala Leu Phe Leu Arg Val 20 25 30Lys Phe Ser Arg Ser Ala Glu Pro Pro Ala Tyr Gln Gln Gly Gln Asn 35 40 45Gln Leu Tyr Asn Glu Leu Asn Leu Gly Arg Arg Glu Glu Tyr Asp Val 50 55 60Leu Asp Lys Arg Arg Gly Arg Asp Pro Glu Met Gly Gly Lys Pro Arg 65 70 7580 Arg Lys Asn Pro Gln Glu Gly Leu Tyr Asn Glu Leu Gln Lys Asp Lys 85 9095 Met Ala Glu Ala Tyr Ser Glu Ile Gly Met Lys Gly Glu Arg Arg Arg 100105 110 Gly Lys Gly His Asp Gly Leu Tyr Gln Gly Leu Ser Thr Ala Thr Lys115 120 125 Asp Thr Tyr Asp Ala Leu His Met Gln Ala Leu Pro Pro Arg 130135 140 35 amino acids amino acid unknown linear protein 45 Arg Val LysPhe Ser Arg Ser Ala Glu Pro Pro Ala Tyr Gln Gln Gly 1 5 10 15 Gln AsnGln Leu Tyr Asn Glu Leu Asn Leu Gly Arg Arg Glu Glu Tyr 20 25 30 Asp ValLeu 35 32 amino acids amino acid unknown linear protein 46 Lys Lys LeuVal Lys Lys Phe Arg Gln Lys Lys Gln Arg Gln Asn Gln 1 5 10 15 Leu TyrAsn Glu Leu Asn Leu Gly Arg Arg Glu Glu Tyr Asp Val Leu 20 25 30 35amino acids amino acid unknown linear protein 47 Arg Thr Gln Ile Lys LysLeu Cys Ser Trp Arg Asp Lys Asn Ser Ala 1 5 10 15 Ala Asn Gln Leu TyrAsn Glu Leu Asn Leu Gly Arg Arg Glu Glu Tyr 20 25 30 Asp Val Leu 35 35amino acids amino acid unknown linear protein 48 Arg Thr Arg Phe Ser ArgSer Ala Glu Pro Pro Ala Tyr Gln Gln Gly 1 5 10 15 Gln Asn Gln Leu TyrAsn Glu Leu Asn Leu Gly Arg Arg Glu Glu Tyr 20 25 30 Asp Val Leu 35 36amino acids amino acid unknown linear protein 49 Arg Thr Arg Asp Pro GluMet Gly Gly Lys Pro Arg Arg Lys Asn Pro 1 5 10 15 Gln Glu Gly Leu TyrAsn Glu Leu Gln Lys Asp Lys Met Ala Glu Ala 20 25 30 Tyr Ser Glu Ile 3538 amino acids amino acid unknown linear protein 50 Arg Thr Arg Ile GlyMet Lys Gly Glu Arg Arg Arg Gly Lys Gly His 1 5 10 15 Asp Gly Leu TyrGln Gly Leu Ser Thr Ala Thr Lys Asp Thr Tyr Asp 20 25 30 Ala Leu His MetGln Ala 35 63 base pairs nucleic acid single linear cDNA 51 GGATCCCAAGGCCAGGCTAA AGCCGAAGCC GCGAAGGCCG AGGCTAAGGC CGAAGCAGAT 60 CTG 63 20amino acids amino acid unknown linear protein 52 Asp Pro Lys Ala Glu AlaLys Ala Glu Ala Lys Ala Glu Ala Lys Ala 1 5 10 15 Glu Ala Asp Leu 20 76amino acids amino acid single linear protein 53 Arg Lys Lys Arg Ile SerAla Asn Ser Thr Asp Pro Val Lys Ala Ala 1 5 10 15 Gln Phe Glu Pro ProGly Arg Gln Met Ile Ala Ile Arg Lys Arg Gln 20 25 30 Leu Glu Glu Thr AsnAsn Asp Tyr Glu Thr Ala Asp Gly Gly Tyr Met 35 40 45 Thr Leu Asn Pro ArgAla Pro Thr Asp Asp Asp Lys Asn Ile Tyr Leu 50 55 60 Thr Leu Pro Pro AsnAsp His Val Asn Ser Asn Asn 65 70 75

What is claimed is:
 1. A cell which expresses a proteinaceous cellmembrane-bound chimeric receptor, said receptor comprising (i) anextracellular CD4 portion which specifically recognizes and binds HIV oran HIV-infected cell and (ii) a transmembrane domain, wherein saidchimeric receptor does not mediate HIV infection of said cell expressingsaid chimeric receptor.
 2. The cell of claim 1, wherein said CD4 portionconsists of amino acids 1-394 of SEQ ID NO:
 29. 3. The cell of claim 1,wherein said CD4 portion consists of amino acids 1-200 of SEQ ID NO: 31.4. The cell of claim 1, wherein said receptor further comprises anintracellular portion and the CD7 transmembrane domain of SEQ ID NO: 35.5. The cell of claim 1, wherein said receptor further comprises anintracellular portion and the hinge, CH2, and CH3 domains of the humanIgG1 molecule of SEQ ID NO:
 33. 6. The cell of claim 1, wherein said CD4portion is projected away from said cell membrane by at least 48angstroms.
 7. The cell of claim 6, wherein said CD4 portion is projectedaway from said cell membrane by at least 72 angstroms.
 8. DNA encoding achimeric receptor of claim
 1. 9. A vector comprising the chimericreceptor DNA of claim
 8. 10. A proteinaceous cell membrane-boundchimeric receptor comprising (i) an extracellular CD4 portion whichspecifically recognizes and binds HIV or an HIV-infected cell and (ii) atransmembrane domain, wherein said chimeric receptor does not mediateHIV infection of said cell expressing said chimeric receptor.
 11. Thereceptor of claim 10, wherein said CD4 portion consists of amino acids1-394 of SEQ ID NO:
 29. 12. The receptor of claim 10, wherein said CD4portion consists of amino acids 1-200 of SEQ ID NO:
 31. 13. The receptorof claim 10, wherein said receptor further comprises an intracellularportion and the CD7 transmembrane domain of SEQ ID NO:
 35. 14. Thereceptor of claim 10, wherein said receptor further comprises anintracellular portion and the hinge, CH2, and CH3 domains of the humanIgG1 molecule of SEQ ID NO:
 33. 15. The receptor of claim 10, whereinsaid CD4 portion is projected away from said cell membrane by at least48 angstroms.
 16. The receptor of claim 15, wherein said CD4 portion isprojected away from said cell membrane by at least 72 angstroms.